sjbarnes
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Windows Server 2008 R2 Maximum number of SCSI ID's
Hi,
What is the maximum number of SCSI ID's Windows Server 2008 R2 can handle? Our SAN team have allocated 306 SCSI ID's for LUNS but when they try and allocate LUNS with SCSI ID's over this number the Windows Server cannot see them.
Our SAN team seem to think there must be a SCSI limit of 306 on Windows Server 2008 R2, although this number does seem a bit random.
Could anyone confirm what the maximum number of SCSI ID's Windows Server 2008 R2 can handle please?
Many thanks in advance!
What is the maximum number of SCSI ID's Windows Server 2008 R2 can handle? Our SAN team have allocated 306 SCSI ID's for LUNS but when they try and allocate LUNS with SCSI ID's over this number the Windows Server cannot see them.
Our SAN team seem to think there must be a SCSI limit of 306 on Windows Server 2008 R2, although this number does seem a bit random.
Could anyone confirm what the maximum number of SCSI ID's Windows Server 2008 R2 can handle please?
Many thanks in advance!
There are also per LUN limits as well.
You can have up to 256 LUNs per host, and up to 8 paths to each of those LUNs.
256 luns * 4 paths each, or 128 luns with 8 paths each
Doesnt your RAID array/SAN present server based LUN numbers to each server?
Why would you ever want anything close to 255 LUNs on a server? Back before Hyper-V 2008 R2 when I had 1 LUN per VM I would get up to 20 LUNs or so but hundreds of LUNs on a server doesn't seem like a good idea.
Kevin, i think he means that the LUN numbers are up in the 300's not that he has 300 LUNs or i hope thats what he means!
All the storage systems i have worked with have always had a mechanism to present the server with the LUN number of your choice.
All the storage systems i have worked with have always had a mechanism to present the server with the LUN number of your choice.
ASKER
Hi,
Thanks for the info. It does now look like the SAN has a limit to provide 255 SCSI ID's, not really my area of expertise.
We require this numer of LUNS due to implimenting Exchange 2007 in a 3 Active server/1 Passive server config with a total 50 SG to per server. Microsoft recommend 1 x LUN for DB and 1 x LUN for LOGS this totals 100 LUNS per server, and as this is a cluster each server needs to see each others LUNS for failover etc so thats where the 300 LUNS comes from..........
Thanks for the info. It does now look like the SAN has a limit to provide 255 SCSI ID's, not really my area of expertise.
We require this numer of LUNS due to implimenting Exchange 2007 in a 3 Active server/1 Passive server config with a total 50 SG to per server. Microsoft recommend 1 x LUN for DB and 1 x LUN for LOGS this totals 100 LUNS per server, and as this is a cluster each server needs to see each others LUNS for failover etc so thats where the 300 LUNS comes from..........
So you have 100 tiny LUNs per server? Seems like overkill?
How are these LUNs implemented in the SAN as it sounds like this scheme could be very wasteful in terms of the number of disks.
How are these LUNs implemented in the SAN as it sounds like this scheme could be very wasteful in terms of the number of disks.
ASKER
Hi,
Yeah we have 100 LUNS per server. May seem like overkill but it is needed as we are talking about potentialy hosting 23,000 mailboxes!
Yeah we have 100 LUNS per server. May seem like overkill but it is needed as we are talking about potentialy hosting 23,000 mailboxes!
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ASKER
Hi Connollyg,
Sorry for any confusion but I don't deal with the SAN myself.
The SAN team have now set the SCSI ID's as you have recommended and all appears to be fine now.
Thanks!
Sorry for any confusion but I don't deal with the SAN myself.
The SAN team have now set the SCSI ID's as you have recommended and all appears to be fine now.
Thanks!
i am pretty sure there is a limit but as you already stated "a bit random". I looked through all the "Windows Server 200X Storage limit" guides and searched the Hyper-V, MS Storage Server Guides/Limits Whitepapers and the limits are 255.
HP states above 255 will not work:
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c02730973&lang=en&cc=us&taskId=101&prodSeriesId=4132949&prodTypeId=3709945
And i can't assign higher ID's in IBM Storage Manager for example, so i would think this is a limit to SCSI. Vmware also has a problem with ID's 254+