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AlexWhit
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Server slow to replicate

Post by AlexWhit »

i wonder if you can help. i have veeam running to replicate server.

the issue is i have one server taking 30+ min to replicate where the others may only take 3-4 min. would this be because the hard drives on the guest are set to thick provisioned?

it seems to have to replicate all the drive and not the changes.

the speed seems to be at about 68 MB/s where as the other guest servers are only at maybe 9 - 10 MB/s

Vitaliy S.
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Re: Server slow to replicate

Post by Vitaliy S. »

Hi Alex,

What type of VM is this? Is it a SQL Server, Exchange? Do you have CBT enabled for this VM? Also can you please tell me the bottleneck stats for the VM replication session?

Thanks!

AlexWhit
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Re: Server slow to replicate

Post by AlexWhit »

it is a windows server 2003 terminal server. CBT is not enabled. i am trying to enable it but for some reason it will not enable.

Vitaliy S.
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Re: Server slow to replicate

Post by Vitaliy S. »

Please verify if this VM meets the following CBT requirements: Setting Up Changed Block Tracking

AlexWhit
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Re: Server slow to replicate

Post by AlexWhit »

I have had a look though that post and cannot see any snapshots. i change ctkEnabled to true and then set the correct scsi to true. reboot and it then disables it again. do you think it is CBT that is making it replicate the entire hard drive?

Vitaliy S.
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Re: Server slow to replicate

Post by Vitaliy S. »

The entire hard drive is never replicated during the incremental job pass. If VMware change tracking cannot be enabled for some reason, the entire VM hard drive is read to identify changed blocks (this is performed by our proprietary change tracking engine) and then only changed blocks are replicated to the target side. Be aware that this operation might take the same amount of time required to transfer the entire disk, I guess this is what have confused you.

AlexWhit
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Re: Server slow to replicate

Post by AlexWhit »

i think i have CBT enabled now but it still looks t replicate allt he drive

Vitaliy S.
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Re: Server slow to replicate

Post by Vitaliy S. »

Do you see [CBT] tag next to each virtual disk in the real-time statistics?

AlexWhit
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Re: Server slow to replicate

Post by AlexWhit »

it was. but then on the next one it wasnt

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Re: Server slow to replicate

Post by AlexWhit »

it is like it keeps turning it off

Vitaliy S.
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Re: Server slow to replicate

Post by Vitaliy S. »

Hmm...Veeam backup job cannot disable CBT on your VMs, I suggest taking a look on your debug logs to understand what's going on (our support can you help you with this task). Generally, once you CBT is enabled it shouldn't failback to the turned off state. Are you sure you don't have any snapshots? What does this Veeam ONE report say for this VM?

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