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Forum Newbie
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Last Login: Saturday, May 17, 2008 9:40 AM
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Appreciate if you can answer a few questions for VSA/VI3.
1. What kind of SCSI reservations does LeftHand VSA support (SCSI-2 or SCSI-3/persistent)?
2. Is there a place where I can get maximum config numbers?
For example, maximum num of iSCSI volumes, clusters, snapshots, max no of connections/session
3. How can one enable Multi-pathing using ESX iSCSI Initiator?
4. Max disk size: I understand it is 2 TB per VMDK. So, if there are 2 VSA nodes (with 2 TB each), I can get a storage pool of 4 TB (when used for non-replicated iSCSI Volumes).. is this correct?
Thanks,
Karthik
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Supreme Being
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Last Login: Today @ 3:37 PM
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1. What kind of SCSI reservations does LeftHand VSA support (SCSI-2 or SCSI-3/persistent)?
Both are supported in SAN/iQ, I think only Win 2008 clusters actually use SCSI-3/persistent today though.
2. Is there a place where I can get maximum configuration numbers?
For example, maximum number of iSCSI volumes, clusters, snapshots, max no of connections/session
I don't think they are published in one spot today other than some specifics on the VSA in the VMware SAN compatibility guide.
The numbers are really flexible because the more nodes there are and their individual speeds effect the numbers. I think we are publishing some specific configurations and their numbers for SAN/iQ 8 though since there is a ton of testing going on around this right now.
Targets? I know for SAN/iQ 7 VSA, configured at the minimum requirements for RAM and CPU, can do 16 iSCSI targets per node in a cluster. That is what it was certified to do in the VMware HCL (You'll see that in the HCL itself). Real SAN/iQ nodes do much more.
Nodes per cluster? We've tested up to 40. I don't think I've ever seen a production one over 30 though. Usually there is some business / application / or network infrastructure reason to break up a cluster long before then. 3 to 12 node clusters seem to be the most popular.
Snapshots? No hard limit. I don't see customers doing more than 50 per volume though. 5 to 8 per volume is common.
Connections / Session? For SAN/iQ session and connection are the same, so 1:1.
3. How can one enable Multi-pathing using ESX iSCSI Initiator?
You mean the software initiator? Only way to do that today would be ESX 3.5, and requires multiple subnets. Not much worth the effort IMHO. You only need one session to get full redundancy on a SAN/iQ SAN. Only seems like HBAs ever use multi path on ESX because they need nic port fail over. I do expect there to be better multi path support in ESX and the ability to customize it for SAN/iQ in the near future (near = months not years). That will be nice because we could improve IO paths for clustering like we do for windows today.
4. Max disk size: I understand it is 2 TB per VMDK. So, if there are 2 VSA nodes (with 2 TB each), I can get a storage pool of 4 TB (when used for non-replicated iSCSI Volumes).. is this correct?
Bingo. And a 5 node cluster of VSA could do a unreplicated 10TB LUN or a replicated 5 TB LUN. Using thin provisioning and over committing you could go much bigger of course.
Hope that helps.
Adam C
Product Manager
LeftHand Networks
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