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lloyd.mills
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Target Proxy "Direct SAN Access"

Post by lloyd.mills »

Hello,

I am running a replication job from one site to another, using a proxy at each site.
Each proxy is directly connected to the SAN at it's site.

The source proxy is using Direct SAN Access "[san;nbd]".

However, the target proxy does not use Direct SAN Access, it is however connected to the destination SAN.

Local backup's from this proxy do use Direct SAN Access.

Has anyone come across this?

Is this the desired behaviour?


Cheers

Lloyd

Vitaliy S.
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Re: Target Proxy "Direct SAN Access"

Post by Vitaliy S. »

Lloyd,

This is expected as replication jobs do not use vStorage API direct SAN mode to write VM data to destination hosts, because of the the reasons described in our sticky F.A.Q. topic.

We are using hot add mode instead, which in turn writes data to the storage through the host's storage I/O stack. If hot add is not possible, all the data goes through network stack.

Thank you!

rrkerr
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Target proxy SAN mode problem with offsite replication

Post by rrkerr »

[merged]

The problem I have is with the proxy in the DR site not using SAN mode to access the target data-store, even although the server has SAN access and the VMFS luns are visible to the server in disk management.

The source proxy has no problem with SAN access mode, as shown from this log extract.
16.05.2012 10:22:10] <01> Info [ProxyDetector] Trying to detect source proxy modes for VM [VMAPPL01]
[16.05.2012 10:22:10] <01> Info [ProxyDetector] Detecting storage access level for proxy [VMware Backup Proxy]
[16.05.2012 10:22:10] <01> Info [ProxyDetector] Detecting san access level

[16.05.2012 10:22:10] <01> Info [ProxyDetector] All disks are accessible through san
[16.05.2012 10:22:10] <01> Info [ProxyDetector] Detected san storage access level for proxy [VMware Backup Proxy] - [FullSan]
[16.05.2012 10:22:10] <01> Info [ProxyDetector] Detected mode [san;nbd] for proxy [VMware Backup Proxy]
[16.05.2012 10:22:10] <01> Info Target data is not initialized.

[16.05.2012 10:22:10] <01> Info [ProxyDetector] Trying to detect target proxy modes
[16.05.2012 10:22:10] <01> Info [ProxyDetector] Detecting storage access level for proxy [VMware Backup Proxy]
[16.05.2012 10:22:10] <01> Info [ProxyDetector] Detected mode [nbd] for proxy [VMware Backup Proxy]


The job is configured on the DR Veeam server, to replicate VMs from the primary site to DR. Each site has a physical Veeam server with v6 update 3 installed, each attached to their local SAN. Veeam was installed in each site using the default settings and the proxy on each server is the default VMware Backup Proxy. The job specifies the source proxy and target proxy rather than being left to auto select. The storage access is left at auto.
It's my understanding that the source proxy should read the data from the VM to be replicated using SAN mode, compresses and sends the data to the target proxy, which in turn should decompress and write the data to the target storage which it's connected directly to, in SAN mode. However, the target proxy always fails to NDB mode, resulting in mega poor performance and timeouts.
Have I misunderstood how offsite replication with a proxy in each site works, or is the target proxy trying to access the primary site storage for some reason?
Can anyone shed any light on the info message Target data is not initialized?

thanks in advance.

foggy
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Re: Target proxy SAN mode problem with offsite replication

Post by foggy »

Ryan, Direct SAN mode cannot be used to populate replica VMs on target host. Only hotadd and NBD modes are supported for writing data to the target destination (this is covered in documentation). Note that you cannot select the mode to be used, it is selected automatically based on the proxy configuration (whenever possible, the hotadd mode is used). So to benefit from the fast replica data population on target, you'd better install an additional virtual proxy on target host.

Thanks.

rrkerr
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Re: Target proxy SAN mode problem with offsite replication

Post by rrkerr »

Yeah, just found it on pg 21 of the user guide. I was too hasty in posting. I will deploy a virtual proxy on the target host as recommended.
Thanks for replying anyway!

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