IScsi - datastores

[chrisjdeane]

Hello,

I have 2 blade servers they are using software iscsi - and sharing a datastore.

My 2 HP blade c class servers are connected to a SAN over iscsi and a dedicated switch - my Lun is fairly full.

I have 5 VM's on 1 and 4 on the other for now.

I want to add 11more servers - I could create an extent but dont want to.

WHats the best way forward - can I add another ISCSI LUN? and put the VM's on this - I presume HA will work still even though there ar 2 different LUNS.

Otherwise I could purchase SAN fibre cards and do it that way? the only thing is the cost!

Regards

C.

[krc1517]

I'd just add a few more luns to both hosts, scan, format and away you go. There shouldn't be an issue with adding additional LUNs to the existing cluster.

Otherwise, you could break the cluster, add the LUNs, recreate the cluster but that isn't necessary.

[dkfbp]

Just add another lun on your SAN and share it for the esx servers. Everything will be fine.

Frank

[psharpley]

That's the way to go. Create additional LUNs as krc1517 says. Choose a suitable size, say, 250 - 300 GB and leave 20% or so free space on each LUN.

[Dave_Mishchenko]

As has been suggested, you'll have no problem adding another LUN (both hosts will need to see the LUN with the same LUN ID) as you've done with the current LUN. Avoiding extents is the best way to go and you could always migrate the current VMs onto the new LUN as well, but 20 VMs would be pushing it for a single LUN. Below is a good thread on sizing new LUNs.

http://www.vmware.com/community/thread.jspa?messageID=649338

[chrisjdeane]

Thanks everyone.

So my original VM's can stay on the original lun and the new ones will go on the new lun.

I wish they had gone for fibre though - backups are going to be a pain!

Thanks for the sizing links - excellent info!

Regards

C.

[psharpley]

I wish they had gone for fibre though - backups are going to be a pain!

So where's the pain?

[krc1517]

Backups would be just as painful using a FC SAN. Currently we use host based backups for our FC SAN VMs w/legato networker.

You could use VCB to help with your backups of the particular VMs or use a LUN snapshotting like SnapMirror if you are using a Netapp.

I think once we finally rollout the BL685c and ISCSI, we'll go with smaller LUNs with less VMs and just have the LUNS that have critical data on them snapshotted and recover them to a recovery lun. Then use the Converter to bring them back in as needed.

should be fun....once we get there.

[chrisjdeane]

Hello,

Thankyou.

I see iscsi is now supported for VCB.

Whats the best way to configure this.

My iscsi network is a dedicated gigabit switch.

We will be using netbackup to do this and will be installing agents in each vm.

Any pointers would be great.

Many thanks

C.

[Texiwill]

Hello,

To use VCB with iSCSI, the LUNs on the iSCSI server must be presented (iSCSI initiator) to your Windows VCB proxy. Then VCB works just like it does for a FC SAN. No real magic, just be aware that SCSI Reservation requests may go through the roof.

I like using vRangerPro, or something I wrote myself that uses vcbMounter from the SC CLI. These both backup to a remote data store and from there to tape/disk/DVD.

Best regards,

Edward L. Haletky, author of the forthcoming 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', publishing January 2008, (c) 2008 Pearson Education. Available on Rough Cuts at http://safari.informit.com/9780132302074

[chrisjdeane]

Thankyou for that.

So I can just plug in my VCB server to the dedicated Gigabit switch and use the MSoft Iscsi initiator?

Thats nice to know about the possible performance impact - this shouldnt matter as the backups will be out of hours and the machines wont be used in production during this time.

Any figures on throughput etc?

Its nice to see new books coming soon on ESX 3 - there arent many yet!

Many thanks

Regards

C

[Texiwill]

Hello,

Yes you can use the MS iSCSI initiator. As for performance impact, with my entry level SAN it was so bad I could not even backup within the night. I think it will vary from size of VM to size of VM. Thank you, it has been quite a bit of work and a lot of fun to write. Got to play with everything.

Best regards,

Edward L. Haletky, author of the forthcoming 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', publishing January 2008, (c) 2008 Pearson Education. Available on Rough Cuts at http://safari.informit.com/9780132302074