How to build a Mail Server on an iSCSI SAN with HA?

Low cost SAN with cluster to achieve Failover

I have recently been window shopping for some networking stuff on Amazon. Amazingly, 10GbE NICs and switches of name brands and Cat7 cables are getting cheaper than ever. I started to wonder if I could build a mail server on iSCSI SAN and cluster to make it HA-capable? Since my concept is not totally automated, perhaps I should call it MA (medium availability) rather than HA (high availability)? LOL…

Name Brand Solution

For the past two decades or so, mail server solution on HA cluster must have definitely been available from big names, such as Microsoft Exchange Server, IBM Lotus Domino, Oracle Veritas Cluster Server/Messaging Server and etc. But, the implementation cost of such solutions is rocket-high, like 10 grand, 20 grand or more. They all come with top hardware specs, server license, cluster license, cluster node license, mail server connection license, directory service connection license, tech support tickets, man labor and blah blah.

Amazon Solution

In 2019, prices on SSD and 10GbE parts are dropping and getting more accessible than ever. DIY iSCSI SAN and HA cluster implemntation makes this solution no longer for enterprise only. My DIY idea comes from equipping mail server with more advanced but less expensive NAS gadgets as well as lower cost PCs for cluster purpose.

Theory

According to 10GbE spec sheet, the 10Gb/s transmitting speed is roughly 1250MB/s, which is 1.25GB/s. For SATA-3, it is about 6Gb/s and that turns out to be 750MB/s.

Dual-port 10GbE NIC

In the reality, there must be some bandwidth loss during network transmission due to many factors. Thus, let’s cut 1.25GB/s in half and it is 625MB/s. For SATA-3, let it optimally remain 70% of spec value and make it 525MB/s. The 625MB/s outruns 525MB/s during data transmission no matter what and it is unprecedented in the past.

Next, we will discuss about software and hardware spec that compose the iSCSI SAN & HA Cluster infrastructure.

Network Speed

In the past, 1GbE NIC used to be good enough upgrading from 100MbE NIC. At that time, perhaps only data center could afford 10GbE equipments. Nowadays, these gadgets have become so affordable for regular users. To achieve 10GbE transmission speed, it requires SFP+ (copper or fiber) or RJ-45 (Cat6 or Cat7 cable) for cabling between Cluster Server and NAS.

SSD storage

Just about one year ago, a 1TB SSD used to be over USD$400. Recently, 1TB SATA-3 SSD is running about USD$150 and it is dirt cheap comparing what it used to cost. For my personal brand preference, I use either Micron or Intel:

Crucial MX500 2TB

• Crucial/Micron MX500 2TB: USD$289 / 1TB: USD$134
• Intel 545S 1TB: USD$222

Synology NAS

Due do gradual price drop on SSD drives over time, building a RAID-5 or -6 based on 4 Micron 2TB or 1TB SSD is a great news for IT staff because users will less likely complain about poor disk performance. For non-IT people, NAS is an easier solution. When it comes to Synology NAS, I think DS1517+ is not a bad choice. Also, to achieve my design of iSCSI NAS plus HA Cluster Mail Server, DS1517+'s hot-swappable HDD capability and expandability to 10GbE E10G18-T2 (dual-port high-speed 10GBASET add-in card) are must-have. By the way, upgrading memory module to 16GB for the best performance is a great plus.

Synology DS1517+

So far, issues of mail data backup and contingency plan are resolved on Synology unit. For example, on DS1517+, we can store mail data on a RAID-5 composed of 4 SSDs. Then, install a 4TB conventional HDD on the 5th drive bay for storing ancient mail archive as well as virtua disk images of Windows and Windows Backup data. Or, another option is using the 5th drive bay for SSD cache and it is not a bad idea either.

Cluster PC

• Hardware: Buy two computers with specs of Intel i7, 16GB RAM, and one 120GB SSD. Equip each PC with 10GbE NIC for connections with NAS. The built-in 1GbE NIC is used to connect to switch or router. Then, do we still need additional NIC for cluster heartbeat? We will discuss about it later in this article.
• Software: Install Windows 10 and EVO Mail Server on each of PC described above. Then, do we need to deploy VMWare Workstation to virtualize the mail services? Also, we will discuss about it later in this article.

Cluster Heartbeat Myth

Generally, a separate NIC will be installed on each member PC of a cluster group for heartbeat purpose. Windows Server 2008, 2012 and 2016 and Linux Server have this built-in feature of hearbeat. But, there is no such feature on Windows 10, which is a part of my design for money saving. I also googled it but found no answer. If you happen to know any such tool software available for Windows 10, please let me know and thanks in advance.

The purpose of hearbeat feature works along with quorum disk to automatically determine whether the backup server should take over the primary server or not. I think such automated decision makings should be used on mission-critical servers, such as web servers or database servers.

For mail server, from another point of view, I do not think mail server operation is that mission-critical. With a bit higher fault-tolerance, IT staff can take a a few minutes to diagnose what went wrong and then judge if backup server should take over the primary server. Factors on decision-making:

• Resolving issues on primary server and continue?
• Immediate action of taking over primary server?

In general, issues are likely to be one of the following incidents:

• Hardware: mainboard, memory module, harddisk, power, NIC, network cable – If parts replacement is not readily available, then switch to backup server asap.
• Software: Bugs on OS or mail server software – If opearting system is breaking down and cannot boot up, then switch to backup server asap. If a bug can be fixed within 10 minutes or so, such as a version update or parameter adjustment, then there is no need to switch.

There may be some delay on restoring mail service before IT staff diagnoses issues and makes decision. However, it is always not a bad idea if IT staffs keep the whole situation under control.

Necessary to deploy VMWare?

Whether or not deploying VMWare is a debatable issue. I think if there is sufficient fund, then it is always better to prepare additional contingency plan other than a cluster backup server by installing VMWare Workstation on the primary server.

VMWare Workstation 15

This is how I plan:

• On the primary server, install a virtual Windows 10 under VMWare Workstation. Let’s call it VM A.
• Once VM A runs mail service properly, shut it down.
• Install another 120GB SSD on primary server.
• Copy VM A image file to the new SSD and make it VM B.
• Let’s assume that the primary server hardware is working. Under the circumstance that VM A image is broken, we can immediately start VM B to continue mail services.

Backup server taking over primary server

In the case of deploying EVO Mail Server, since all data of mail, certificate and configuration and etc are all located on NAS, the role of cluster PCs is solely for running mail server services, accessing NAS data, and communicating with LAN/WAN. Each IT staff has his or her own preference on switching from primary server to backup server. I list some of the ways below for you to make decision on which one fits your need:

• If servers are inside LAN:
• Log in router and change the LAN IP under Port Forwarding page (some router calls it Virtual Server) to backup server's internal IP.
• If you always bring primary server offline first before throwing backup server online, then we can disconnect backup server from the network by turning off its NIC while standing by. When the switch-over is about to take place, we turn backup server’s NIC back on. In this scenario, backup server’s LAN IP can be configured as the same as primary server’s. The downside of it is that we cannot perform the swtich-over remotely and have to do it by actually logging in the backup server.
• For the above method, there is a workaround. While backup server is standing by, its NIC is enabled and assigned with an separate internal IP other than the primary server’s IP to avoid conflict. Before switching-over, disconnect primary server from the LAN first. Then, log in the backup server and change its LAN IP to primary server’s IP.
• If the primary server is equipped with VMWare and if server’s hardware is working normally but VM A image is corrupted, launch VM B image to take over mail services. (Note: VM A and VM B have the same public IP)
• If servers are in DMZ or directly connect to Internet:
• Log in DNS hosting service or your own DNS server first. Then, modify IP of mail server host name’s (literally MX record) A record to backup server’s public IP. Such DNS record modification will usually take mintues to a few hours to kick in.
• If the primary server is equipped with VMWare and if server’s hardware are working normally but VM A image is corrupted, run VM B image to take over mail services. (Note: VM A and VM B have the same public IP)

Note:

• Before switching-over, if the primary server is still accessible, simply log in the server and de-activate EVO Mail Server license key first.
• Before switching-over, if the primary server already inaccessible, use other email account to contact EVO staff and let them manually de-activate license key. Then, activate the license key again on backup server.
• To make switch-over quicker, purchase two EVO Mail Server licenses, one for primary and one for backup, and activate them separately. Once backup server is active, copy its license.dat file to the license key folder location on NAS and overwrite the existing one. Then, start mail service.
• If VM images solution is deployed, there is no need to de-activate and re-activate since both VM A and VM B are actually identical. However, make sure not to boot up both images at the same time. Otherwise, both Windows license and mail server license will conflict each other.
• The last one is even easier. Install identicaal hot-swappable drive bays on both servers. If any hardware parts fails but the 120GB OS SSD. Then, simply take out drawer containing the OS SSD. Stuff it into backup server's drive bay and boot up immediately. However, it is recommended to prepare a spare ready-to-boot 120GB OS SSD aside.

Build NAS, iSCSI SAN and Cluster PC together

Let’s assume EVO Mail Server is operating normally. For installing, configuring and testing EVO Mail Server, please refer to this article.

1. On Synology NAS, create iSCSI storage:
• If NAS storage volume has not been created, follow instruction here. If already created, go to next step.
• Now, build TARGET and build LUN. If they have been configured, then skip this part or make slight modification if necessary.
• Open iSCSI Manager.

  

  Synology iSCSI Manager

• Let’s start from scratch.

  

  iSCSI overview

• Click on Target to the left and click on Create.

  

  Create target

• Enter name and IQN as well as making decision to enable CHAP or not.

  

  Create target setting

• The next step is mapping LUN. Here, we will click on Create a new iSCSI LUN.

  

  Create new LUN mapping

• Define capacity of iSCSI LUN.

  

  Determine volume size

• Confirm settings and click on Apply to save settings.

  

  Target confirm settings

• Click on Target to the left again to double-check settings.

  

  Target summary

• Click on LUN to the left again to confirm if target mapping is connected.

  

  LUN summary

• Click on Settings to the left to increase I/O Queue Depth value. Setting a greater value will improve 10GbE network connectivity and SSD performance.

  

  I/O Queue Depth Value

• Finally, click on Overview to confirm whether iSCSI has already been properly configured.
2. Enable iSCSI initiator in Windows 10.
• There are a few articles that you can read through on what can be done for iSCSI optimzation on Windows end.
• How to optimize your iSCSI service for Windows
• How to use iSCSI Targets on Windows computers with Multiple Connections per Session (MC/S) support
• How to Use iSCSI Targets on Windows Computers with Multipath I/O
• Next, search iSCSI initiator and open it in Windows 10.

  

  Search for iSCSI initiator

• In iSCSI initiator window, under Targets tab, enter NAS IP and click on Quick Connect… button to initiate a quick search and connection.

  

  Enter iSCSI target IP

• In Quick Connect window, available target is listed and the state is connected.

  

  Quick Connect window

• Upon closing Quick Connect window, Discovered targets will list the connected NAS as well.

  

  Discovered target

• Search Computer Management and open it in Windows 10.

  

  Search for Computer Management

• Click on Storage/Disk Management and the newly created disk is already listed.

  

  Convert to GPT

• In the screenshot above, mouse right-click on Disk 2 area and click on Convert to GPT Disk. Why GPT? GPT enables creating partition beyond 2.2TB.
• Next, mouse right-click on area of newly created partition to continue creating volume and formatting it.

  

  New Simple Volume Wizard

• Check the formatted disk. 

  

  New Simple Volume Wizard

3. Move mail server related data to iSCSI disk.
• Open EVO Mail Server GUI. Click on Status page and scroll down to Server setting status.

  

  EVO Mail Server Server setting status

• In the screenshot above, click on arrow loop symbol to the right of Mail Data Folder. There will open a window browsing folder tree.

  

  EVO Mail Server Server setting status

• Once a folder is selected, click on OK. There will be a Reminder popping up and inform actions being taking place.

  

  EVO Mail Server Server setting status

• Once data migration is complete, another Reminder will pop up and inform actions taken place.

  

  Mail Data Relocation Summary
• At the moment, Mail Data Folder is displaying new folder location.

  

  Mail folder location relocated

4. Finally, perform testing routines described in the setting up mail server article I mentioned previously.

Price breakdown

Nowadays, running a company with 100 to 200 employees is never an easy task. IT infrastructure investment ought to be carefully assessed. Here is a rough price quote for what it costs to build this solution:

• Intel i7, 16GB RAM, 120GB SSD, 10GbE NIC (options are fiber and RJ-45), 450W power supply, Windows 10 computer x 2, USD$2000
• Synology NAS DS1517+ x 1, USD$1000
• Synology DDR3 Memory Module, USD$300
• Synology E10G18-T2 or E10G17-F2 NIC x 2, USD$270 or USD$257
• Micron MX500 2TB SSD x 4, USD$1200
• WD 4TB HD (Mail Archive HD) External (if 5th drive bay is used for SSD cache) or Internal (if using 5th drive bay) x 1, USD$99 or USD$169
• VMWare Workstation 15 x 1, USD$249 (optional if VMWare VM A and VM B solution is deployed)

All prices above are just random search from Amazon. The total price may be cheaper than USD$15000 if looking around more. But, the bottomline is that 10GbE NIC and TB-grade SSDs must stay. Here are comments on particularly these two parts:

• NIC: If possible, use fiber NIC. You will be rewarded with much better performance.
• NAS: Other than DS1517+, DS1817+ (8GB RAM version, USD$1400) is a good choice. It has two 10GbE ports built-in. Yet, two drive bays can be used for building SSD cache while there are still six drive bays for constructing RAID-5 or -6. Any idea on sizes for SSD cache drives? Consult your SSD dealer or check out this article. Though DS1817+ is USD$200 more expensive than DS1517+, RAM modules and 10Gbe NIC are taken care of. The overall expenses on NAS is USD$200 less at least. Nevertheless, hardware spec on NAS varies from one to another. It is up to you to decide.
• NAS SSD: Why I strongly recommend on getting 2TB SSDs? Based on technical aspect, the bigger capacity the faster speed it is. Hence, if I were you, I would get 2TB SSDs once for all and it will definitely last longer.

Conclusion

It is a long article and it took me a long time to wrap it up. I just happened to write this article because I thought that we can benefit from huge price drop on both 10GbE NIC and TB-grade SSD. There are definitely other ways of implementation giving even faster performance, such as stuffing several PCI-e and NVME SSDs directly into mail server machine itself.

But, my main focus this time is providing a low-budget solution that offer fault tolerance for mail server. For exqmple, NAS running on RAID-5 or -6 provide fault-tolerance for storage while cluster deployment provides fault-tolerance for hardware failure.

At last, this article is for your reference when you happen to build a fault-tolerance mail server. However, each company has different IT environment. Perhaps you can survey on all left-over IT assets that are sitting around first. Then, purchase what is missing. Eventually, you will save even more for yourself or for your boss. Hope your server keep running and lasting. Yet, you can have sweet dreams every night with no emergency call from IT colleagues.

How to auto BCC in Outlook?

What is BCC in email?

In term of e-mail knowledge, BCC means Blind Carbon Copy. It serves a purpose of sending extra e-mail messages to another party without acknowledging recipients in both To: and CC: fields of such forwarding action.

In Outlook 2016/2019, auto BCC is missing?

If you use Outlook at work, you probably have met some situation where you need to BCC outgoing e-mail messages to your boss for various reasons. However, when you click on New Email to start writing, you do not see BCC field anywhere. How do we display BCC field?

auto bcc outlook

It is easy! In New Email window, simply click on OPTIONS on menu and click on Bcc button above Show Fields. Then, you will see an extra field of Bcc... popping up below Cc.... This field will stay there permanently in the future when you write new e-mails.

How to BCC sender itself?

When an e-mail is sent, there will be a copy in Sent Items (Items sent) folder. It is technically a way of auto BCC sender itself. However, it is hard to trace a particular e-mail among hundreds of sent items. This method does work out very well.

Some thinks that you can create a rule to send a copy of sent emails to a specified folder when some pre-defined conditions are met. But, there is one drawback that you cannot filter BCC yourself the outgoing mails.

outlook auto bcc myself

Auto BCC via VBA scripts?

By using Outlook's Rules and Alerts feature, it is only possible to CC to other e-mail addresses. Then, how to perform auto-BCC? Please refer to this article of How to send Auto BCC Outlook 2016. It is not as efficient for regular desktop users because it requires certain knowledge of program coding and it is not ready to use.

Auto BCC via Third-party Outlook Add-in?

The simplest way to get the job done is using a third-party Outlook add-in. There are a few venders out there, such as Power Toys for Outlook's ABCC, AbleBits's Auto BCC, and etc. The concept is as straight forward as listing BCC recipients, defining filter rules and done.

outlook auto bcc setup

Using an add-in with filter to trigger auto-BCC enables users to selectively send e-mail messages when certain conditions are met. It fits better into daily practice unlike auto BCC via VBA forwarding every e-mail every time.

For example, Power Toys for Outlook's ABCC feature picks 5 fields within an e-mail that most depicts intentions or purposes of what this e-mail is about. With From, To, Subject, Body, and Attachment file name, users can easily filter keyword-related e-mails and send them to some mailboxes they want. The best part of this auto-bcc feature is that the original recipient will not be aware of this secret e-mail forwarding on the back.

However, our suggestion to intended users is using this feature wisely. Be aware of what you are doing and do not attempt any unnecessary law violation.

How to share calendar between outlook 2007 and 2010?

How to share calendar between outlook 2007 and 2010?

How to share an Outlook calendars with other people without Exchange server? This is a simple question with no easy answer. If you go to Microsoft website, they will tell you that you can share your calendar by e-mail or an exchange server account. We all know that is not we wanted. Anyway, the above case has been discussed in another article that I wrote: How to share my Outlook calendar with another user?

Let's try another scenario, you have one desktop in office, one desktop at home and one laptop in your car. One of them is Outlook 2007 and two of them are Outlook 2010. Here comes a very easy way to do it:

1. First, you need to get an online calendar account such as fruux, or you can use your existing iCloud or Gmail account.
2. Download EVO Collaborator for Outlook from EVO's Official Site and install it with administrator's privilege. This 5.5MB Outlook add-in is the magic that makes everything possible.
   EVO Collaborator for Outlook, an Outlook add-in from EVO software production
3. Install ECO on your computer at work. In Configure profile(s), select Gmail profile at the left-hand side. Enter your Gmail account at the right-hand side. Click TEST to complete OAuth process. Once you quit Configure profile(s), synchronization will start automatically.
4. Install ECO on your computer at home. In Configure profile(s), select Gmail profile at the left-hand side. Enter your Gmail account at the right-hand side. Click TEST to complete OAuth process. Once you quit Configure profile(s), synchronization will start automatically.
5. Install ECO on your laptop on the road. In Configure profile(s), select Gmail profile at the left-hand side. Enter your Gmail account at the right-hand side. Click TEST to complete OAuth process. Once you quit Configure profile(s), synchronization will start automatically.

From now on, when you turn on any of your computers and open Outlook, ECO will start synchronization and update your calendar events automatically.

Not only between Outlook 2007 and 2010, it can be deployment between all Outlook versions from 2007, 2010, 2013, 2016 to 2019. Yet, if you run your mobile life on iPhone or Android, it would be even more convenient. Let say if you meet someone in business meetings on the road, you simply add new potential customer's contact on your mobile phone. When you go back to office, you will see the new contact entry on your PC's Outlook once sync session is taking place. It will work in similar fashion for future meetings created on the road.

What was mentioned above is a scenario that has always worked for users with Exchange accounts. However, what we are talking about now is a much cheaper alternative that everyone can afford even for a one-man company with no complicated infrastructure involved.

  

Setting up Outlook 2016/2019 with a CalDAV Synchronizer add-in

Setting up Outlook 2016/2019 with a CalDAV Synchronizer add-in "EVO Collaborator"

EVO Collaborator for Outlook syncs your default calendar and address book from your CardDAV or CalDAV server automatically. If you want to synchronize more than one calendar, we recommend setting up additional profile in ECO CalDAV Synchronizer.

Step 1 - Download and install plugin

To sync your CalDAV calendar in Outlook, you need to download and install the plugin ECO Outlook CalDAV Synchronization add-in.

ECO CalDAV synchronizer add-in download

After you installed it on your PC, you need to restart Outlook 2016. The plugin will be available in Outlook ribbon tab at the top.

Step 2 - Select the proper profile and enter correct CalDAV server hostname or URL.

To set up your calendar, you need the CalDAV hostname or URL of your calendar.

If your CalDAV server is already supported by ECO, select the profile directly from the list, such as FastMail.

If your CalDAV server is not supported directly by ECO, log in your Webmail and go to Calendar section. Try to find the CalDAV URL and copy & paste it into ECO's Calendar URL in profile #21.

Enter your username and password. Then click TEST, Apply and Quit.

Step 3 - Open Outlook and click ECO CalDAV Synchronizer

Open Outlook and click the ribbon tab EVO's CalDAV synchronization add-in at the top of your screen.

Step 4 - Click Configure Profiles

Click Configure Profiles to start setting up your calendar.

Step 5 - Add a new profile

Now, you need to configure a profile for your Webmail calendar.

In profiles list to the left, try to locate the service you want to synchronize with.
If your service is not found, try to enter the CalDAV synchronization URL directly.

Step 6 - Select CalDAV folder in Outlook

Next, you need to select the folder where the calendar will be saved on your computer. If you don't change it, default folder will be used.

Click the FOLDER button to the right of Default CalDAV calendar folder name.

Select the Calendar folder under your Outlook Data File (PST) or under your Exchange OST profile.

Step 7 - Enter your server settings

If your server is found in the list, just enter username and password and click TEST.
Otherwise you need to enter your server settings.

• CalDAV calendar URL: the URL you copied from Webmail earlier.
• Username: Your email address.
• Password: Your password.

Then click TEST, Apply and Quit.

Step 8 - All done

Your calendar is now configured. Any change made in Outlook or on Webmail will be synchronized within an interval..

How to share Outlook's calendar with other people?

Without Exchange Server, how to share Outlook's calendar?

Back in the old days, Outlook users could share their calendars with others via Microsoft Exchange Server. However, only users within the same domain could be accessing to the calendars since it is within a proprietary network environment.

Outlook Calendar Sharing

Now, Microsoft started to promote Office365 a few years back after realizing content sharing is getting more popular through Internet. Not only Office, but also its own Outlook.com was merged in with Exchange Online Service as its backend. As a result, individuals other than users within the same domain, such as free Outlook.com users, are able to access shared calendar resource.

HARVARD UNIVERSITY

It is almost summer vacation for schools. Teachers and club staffs may want to plan out agenda of the upcoming school year during summer instead of at last second. But, the fact is that everyone is on vacation and planning trips here and there. 

In the past, teachers and staffs used to hold meetings somewhere they need to physically show up. Then, they would have discussions and use Excel to jot everything down. It was not really effective and yet a good summer vacation was interrupted for some of them.

For now, I suggest that teachers and staffs can create a shared calendar to which every member has access. Whenever there is any idea popped up in mind, just simply create an entry in the shared calendar. By using this collaboration scheme, an outline of agenda for next school year is almost complete. What is left is to wrap it up with some touch and fix on back-to-school day before school really starts.

How to share calendars with users on different platforms?

As we mentioned before, not every teacher or staff has an Outlook.com or Exchange account and gets to add, modify or delete calendar entries. Some has Gmail while some has Yahoo, iCloud or etc. Yet, everyone is on a variety of devices to get online, such as Android, iPhone, desktop PC, or laptop.

As perhaps the most commonly used calendar cloud service provider, Google is strongly recommended. Once this shared Google account is created, every teacher or staff can easily log in this shared Google account from his/her device. Since only one account is being used, everyone logged surely has the privileges to add, modify or delete entries.

How to confgiure shared Google account on different platforms?

Let's talk about how to configure Google account on various platforms.

1. Android:

Android

Whether it is Android phone or tablet, we can log in the shared Google or Gmail account. Then, we can download and install Google Calendar app. Lastly, open this installed app and we will see entries synchronized.

2. iOS:

iPhone

Whether it is iPhone or iPad, we can create Google/Gmail account from within Settings/Passwords & Accounts/Add Account. Then, we can open the built-in Calendar app and put checkmarks in the boxes next to the shared Google calendars. Lastly, we will see the entries.

3. Windows 10/8.1:

Built-in Calendar app within Windows 10/8.1 is rarely used by Windows users because they mostly use Outlook or Thunderbird instead. But, it is working fine. Once a Google account is created within the Calendar app, calendar entries will also be synced.

4. Outlook:

A known fact is that Google Calendar Sync for Outlook was discontinued 4 years ago. Even we downoad and install it on Outlook 2019, 2016, 2013, 2010 or 2007, it would not work because this Outlook add-in cannot connect to Google server. Yet, calendar ics files off Google Calendar can only be imported to Outlook and thus fails serving the purpose of synchronizing. I would rather recommend you to use some third-party Outlook add-in, such as EVO Collaborator for Outlook. Setting up such Outlook add-ins is similar to Google Calendar Sync for Outlook. Once installed, enter username, authenticate through Google OAuth 2.0, configure sync folders and that is all.

5. Thunderbird:

If some teacher or staff is using Thunderbird, then they can refer to Using Lightning with Google Calendar to install & configure Lightning and Provider for Google Calendar. 

6. Mac OS X:

Mac OS X

Like iOS, simply add the shared Google account within Internet Accounts. Once added, open the built-in Calendar application to access shared calendar entries.

How to use Outlook Google Calendar Sync?

Outlook synchronizes with Google Calendar for free

Google used to provide an Outlook add-in, called Google Calendar Sync, that enables users to sync its Google Calendar with Outlook 2007, 2010, 2013, 2016, 2019appplication on Windows. As Google became a bigshot, this freebie was discountinued. In fact, it was not gone but was included in Google App for Work, which turned into GASMO and then G Suite.

I did not use the paid Gsuite after Google Calendar Sync and I turned away to iCloud instead. Some time later, I heard a free Outlook add-in called Outlook Google Calendar Sync aka OGCS was released. Based on my curiosity, I was trying it out and checked how good it was.

Installing and Configuring Steps

1. Download this Outlook add-in from the GitHub website. The most current version is 2.7.0 beta beside the 2.7.5 alpha. I will try it with Windows 10 and Outlook 2016 at the time of downloading and installing.

2. During software installation, there popped up a security warning and we can ignore it. After installation was complete, there would be window with several tabs for further configuration.

3. Click on Settings tab first. Select Google on the side. Click on Retrieve Calendars button.

4. When a Google OAuth window pops up, click on Allow button at bottom.

6. Then, an Authorisation Code will be passed back to OGCS. Next to Select calendar, there will appear the Google account previously selected.

7. Still under Settings tab, click on Sync Options on the side. Let's try configuring the following environment:

• Direction: Select Outlook <-> Google will make it bi-directional sync. Make sure to uncheck 
• Disable deletions and/or Confirm deletions to have both Google Calendar and Outlook to reflect entry deletion in the sync session.
• Attribute to include: Check everything except Use Google default.

8. Next, click on Application Behaviour below Sync Options. Make sure to check both boxes of Start on login and Start in tray.

9. Click on Sync tab and click on StartSync button to see if Outlook calendar entries are being synchronized to Google?

Summary after using Outlook Google Calendar Sync for a few hours: 

It took me 5 to 10 minutes to configure and test out what is what. The following points are for your reference:

Pros:

1. The summary in the console is concise telling you what you need to know. It is good.

2. The Proxy Setting feature is quite useful for users in companies with proxy security.

3. Outlook entries created while Outlook Google Calendar Sync is turned off are still being synced. This is another plus.

4. Though a checkbox of Push Outlook changes immediately is not easily noticeable but still available. The immediate sync after I created something in Outlook is a plus.

Cons:

1. Sync folder assignment on Outlook side is a bit obscure, not quite intuitive enough. It took me a while to realize that I need to define a mailbox to which invitations come in. Then, I get to define to which calendar folder synchronized entries would go.

3. The absence of an Outlook add-in in ribbon UI is a disappointment. I need to call out Outlook Google Calendar Sync console and literally click on StartSync button or call out OGCS's Sync Now from system tray to immediately sync what I just created on Google Calendar to Outlook. 

4. I don't know about you but the shortest automated sync cycle is 10 min for entries on Google Calendar to be reflected on Outlook, which is a bit too long for me.

8. Software update as beta version is a bit slow since 2.7.0 has been out there since 2016. Software maintenance is not quite well managed.

9. Outlook Google Calendar Sync only synchronizes calendar. Other Outlook sync tools of its kind, such as gSyncit, EVO Collaborator for Outlook, OggSync and Sync2, are able to additionally sync contacts, tasks and etc.

In conclusion, OGCS does its synchronizing job as an alternative of Google Calendar Sync. In term of having demands on also syncing additional data other than calendar, such as contact and task, it is not recommended. Tech support wise, all that can be done is to create a new issue on GitHub.