VMware Hot-Add Backup host also a SAN client?

https://www-secure.symantec.com/connect/forums/san-based-backup-0#comment-6626171
VirtualED said:

Using the SAN client feature to backup a VM with a client inside of it is not supported.  SAN Client only supports Qlogic HBA, and the HBA presented in a VM is not a QLogic even if the Host adapter is a QLogic.  A Virtual HBA is always presented in a different format.

A VM cannot be a SAN Client.
And since a Hot-Add host is a VM, and we know that a VM cannot be a SAN Client, it follows that a Hot-Add host cannot be a SAN Client.

Hope that helped.

RLeon

Hi RLeon,

thanks for your reply.

THX

Eric

http://www.symantec.com/business/support/index?page=content&id=TECH130609
http://www.symantec.com/business/support/index?page=content&id=TECH146293

The above technotes are for Backup Exec, and the situation described is not exactly related to yours. For one thing, Backup Exec does not have the SAN client feature.

I post them because I think what you are trying to do is what Symantec would call "Alternative Configurations"; as they are called in the technotes.
Something that is not explicitly documented to be supported, but not entirely impossible to do.
And indeed, people will report that such "Alternative Configurations" can be verified to work.

I couldn't find similar/related technotes for Netbackup. Perhaps someone else could help.

RLeon

When we first started to test VM backups....we tried SAN. Our storage guys had fits when we had to present all datastores to the media servers. I gathered some benchmarks.

We then tried NBD(network). The results were close enough to SAN that we thought it was much safer and our storage guys would quit crying. We have multi 10gb network so the speeds were pretty good. Yes we had to install the agent on all of the VM's...no biggie.

Up until a couple weeks ago...all of my media servers were physical. I built a virtual media server and added it to the mix. I happened to notice one of the backups was using a transfer mode of "hotadd"....and it was running quite a bit faster than the other backups. After researching hotadd....it appears that SAN and hotadd are kind of similar. Hotadd "mounts" \ "adds" the disks it needs within the virtual media server. If you look at disk management on the vitual media server during a hotadd backup....you will see the luns of the VM you are backing up. They are all offline. DO NOT try to on-line them....I believe it will wipe-out the data on these disks. In our enviroment we segregate our datastores by cluster. So if I want to backup the vm's in the test cluster...I must have a vm media server in the test cluster or "share" the datastore access between clusters.

Just as an example....if a single backup on NBD(network) ran at 70mbs....using hotadd it now runs at 110mbs. These numbers are approximate but atleast in my case there is a big improvement.

Since I am very new to hotadd please don't take anything I said as "the way to do it". It seems to work for our enviroment.

Hi Bmitche,

Thank you for this information. Just quick questions regarding your virtual media server:

- How do you send data from the media server? To disk, to tape. Did you define NPIV (Virtual FC Port) to write to tape?

- Are you sure the data is going via the SAN from this media server to its storage Unit?

Many thanks in advance for your reply.

-Eric- 

The data is going from the virual media server to a physical media server which has the MSDP(dedupe pool) and the tape library on it. It goes over our 10gb network. I have a dual 10gb network card in the physical media server and the connections are trunked....so It is a 20gb connection. I assigned a VMXNET3 network adapter to the virtual media server so it also has 10gb network. The data path is... via SAN from my backend storage(HP eva's),(HP 3par),&(HP XP24k) to my virtual media server. Then via dual 10gb network to MSDP, then via internal bus to tape on the physical media server. My MSDP(dedupe pool) is 6gb-SAS connected to the physical media server. The library and drives are 8gb fiber connected to the same physical media server.

Over the next couple months I will be looking at hooking my library and tape drives to the fabric, after that I will try to "grab" some of the shared storage from our disk arrays for MSDP. If I am succsesfull....everything will be traveling over 8gb fiber.

My speeds right now are very good. I am making our backup windows with plenty of time to spare. But there is always room for improvement. Baby steps