Understanding LGTO_Sync issue ..and how to solve it?

[FMorales]

Hello, I notice that in the windows Event Viewer of all my windows 2000 server it show me a "LGTO_Sync" issue when

I do a backup at night of this machines ..... now I know that it is an error that it is an error that appears when the backup utility

(vmbk.pl) try to make the snapshot ....

I run ESX 3.5 and windows 2000 server as VM

I was reading about the problem in various places ...

but in this case I dont have Exchange installed on the server

In some places ask about to disable the "Sync driver" in the vmware tools of the VM .... but I cant find any box with this

option in the vmware tools that are installed on this machines .....

This error cause that sometimes .... (a very few times) the backup fail

What does LGTO_Sync means?

Can I do something for solve the problem?

Thanks a lot

Any suggestions would be very much appreciated!

[Texiwill]

Hello,

Moved to VI: Virtual Machine and Guest OS forum as this is a guest error.

Best regards,

Edward L. Haletky

VMware Communities User Moderator

====

Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education.

CIO Virtualization Blog: http://www.cio.com/blog/index/topic/168354

As well as the Virtualization Wiki at http://www.astroarch.com/wiki/index.php/Virtualization

[jbsengineer]

The Sync driver is responsible for quiescing the drive before a snapshot occurs (which happens before the backup). If you want to disable the Sync driver you can reinstall VMware Tools and uncheck the "Sync Driver" piece of the installation. Beware because your drive cache will not be written to disk you will have a more crash consistent backup.

I disable the Sync driver on my DB servers.

Josh

[jbsengineer]

Oh I forgot the easier way to disable the Sync driver is to go into the Device Manager and choose to Show Hidden Devices. Under the Non-Plug and Play Drivers is the "Sync Driver" just right-click and disable it there. This will require a reboot.

[FMorales]

Ok, for example I have Oracle 8 running in one windows 2000 server .....

and sometimes backups fails with this error so .... do I must disable the sync driver?? would it be recommendable?

The performance of the VM could be slow if I disable the driver?? (The driver only is used when I make a snapshot isnot it?)

If I disable the driver and ... I usually make snapshot of the machine ... maybe the VM could crash??

Thanks you very much

[jguzmanr]

You weren't explicit on the error that you are getting, but it is probably that the lgto_sync driver is waiting for a period when there is no I/O so that it can flush the cache. Since this time doesn't come, the driver cannot do what it is supposed to, hence the error.

If you disable the driver, there will not be a performance decrease (or increase).

The disabling of the driver will not crash the vm while doing a snapshot, as a matter of fact, it will make taking the snapshit quicker as it doesn't have to flush the cache. But as somebody mentioned previously, it will not be crash consistent.

I disable this driver on any database server vm's (SQL, Exchange, etc.).

[jbsengineer]

You definetly will want to disable that driver on your DB servers.

I'm suprised you aren't seeing problems with the DB's when the snapshot is applied. I had several DB's stop in there tracks when the Sync Driver was enabled and the backups started.

[rocker77]

Hello all,

I have problems with VMs which I backup via VCB. Before creating snapshot VM sometime freeze for fifteen minutes. VMware support suggest me disable Legato sync drive.

Those VMs aren't DB servers. They are usually web front-ends, terminal servers and application servers. What I lost with disabling sync driver?

I found info in vi3_35_25_u2_vm_backup.pdf that in U2 version ESX + VMtools sync driver is used only for WinXP and W2k. For W2k3 and above I can use VMware VSS component.

Am I right that with VMware VSS component I will get the same or better (for MS SQL) functionality? What does it means that I won't have file system crash consisten if I disable sync driver?

Thank you for your experiences!!