AppSync 3.5 was installed couple years ago to protect our SQL application. Basically, AppSync agent was installed in SQL cluster. The SQL clusters were running as VMs and the databases were residing in RDM.
Kept getting VSS error that it takes more than 10s to create VSS. That was what MS supported for VSS. If it took more than 10s, the VSS creation step would fail.
Installed latest Solution Enabler 8.4.x.x available at the time and no change. Since the array was VMAX 40k, DNS was not a factor. Eventually, version
Version 3.5.0.1_URM00111091_PRELIM_R2 fix the bug VSS 10s delay bug with VMAX 40k.
Couple things I don't like about the AppSync.
1) Mounting and Dismounting SQL VMFS takes long time and does not work well.
2) Need to reserve an extra copy of luns in the pool
3) If info is not sync, AppSync does not know what to do. So, manually dismount copy from mount host will cause problem because AppSync does not know the luns are dismount. Eventually, contacting support to clean up is required.
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Now, 3 yrs later, AppSync 3.9 was setup for proof of concept few months ago. This time, we have SQL running in VMFS. We encounter same issue as before. Mounting copy to mount host is very slow and timeout. Eventually, we keep our design for SQL as before in RDM. Things are working smoothly with RDM as expected.
We are still using the AppSync 3.5 now until we migrate to AppSync 3.9 next yr. Recently, SQL team change the DB structures and instead of a few larger database, we have a lot of smaller database to be protected. The AppSync host plugin service has memory leak problem. So, we have to setup a process to bounce the service once every 3 days. Hopefully, this won't happen in version 3.9.