Direct SAN access clarification

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Direct SAN access clarification

Veeam Logoby marius roma » Wed Apr 13, 2016 12:23 pm

On page https://helpcenter.veeam.com/backup/vsphere/direct_san_access.html I read that
Veeam Backup & Replication uses the Direct SAN access transport mode to read and write VM data only during the first session of the replication job. During subsequent replication job sessions, Veeam Backup & Replication will use the Virtual Appliance or Network transport mode on the target side. The source side proxy will keep reading VM data from the source datastore in the Direct SAN access transport mode.
Veeam Backup & Replication writes VM data to the target datastore in the Direct SAN access transport mode only if disks of a VM replica are thick-provisioned. If disks are thin-provisioned, Veeam Backup & Replication will write VM data in the Network or Virtual Appliance mode. By default, Veeam Backup & Replication replicates VM disks in the thin format. To write VM data to the target datastore in the Direct SAN access transport mode, select to convert VM disks to the thick format at the Destination step of the replication job wizard.

What does it mean that
Veeam Backup & Replication uses the Direct SAN access transport mode to read and write VM data only during the first session of the replication job
is it the same for backup jobs?
What does it mean that
Veeam Backup & Replication writes VM data to the target datastore in the Direct SAN access transport mode only if disks of a VM replica are thick-provisioned
Is it the same for reading?
I need to speed up backup processes, in which data is read from the VMware datastores in the SAN and written to NAS repositories.
Many disks are stored in thin format.
Given such limitations, is there any real advantage in using Direct SAN access?
Regards
marius
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Re: Direct SAN access clarification

Veeam Logoby foggy » Wed Apr 13, 2016 12:28 pm 1 person likes this post

These limitations affect only population of the target datastore with VM data during replication jobs, backup jobs are not involved.
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Re: Direct SAN access clarification

Veeam Logoby marius roma » Wed Apr 13, 2016 12:58 pm

... so I can expect real performance advantage if I implenent Direct SAN access to backup and restore my VMs even if the disks are thin, is it correct?
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Marius
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Re: Direct SAN access clarification

Veeam Logoby foggy » Wed Apr 13, 2016 1:05 pm 1 person likes this post

Only thick disks can be restored using direct SAN, the same limitations as for replication apply here.
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Re: Direct SAN access clarification

Veeam Logoby marius roma » Wed Apr 13, 2016 1:11 pm

Many thanks.
Marius
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Re: Direct SAN access clarification

Veeam Logoby VladV » Thu Apr 14, 2016 11:33 am

foggy wrote:Only thick disks can be restored using direct SAN, the same limitations as for replication apply here.


Does this limitation apply to NFS Direct as well? The manual does not state this but I wanted to be sure.

Thanks
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Re: Direct SAN access clarification

Veeam Logoby foggy » Thu Apr 14, 2016 12:20 pm

Direct NFS doesn't have this limitation.
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