I'd say you are at the limit for GigE, not knowing anything about your target, increasing your throughput by bonding/teaming would probably give you the best bang for your effort.
IIRC, W2k8 always aligns IO, but in tests I did it showed the improvement to vary from immeasurable to noticeable. Can't comment on the extents... jlc -----Original Message----- From: S Conn. [mailto:sysadminli...@gmail.com] Sent: Monday, May 11, 2009 2:20 PM To: NT System Admin Issues Subject: SQL and iSCSI issue Guys, I need an opinion. Here's the situation: I have a Windows 2008 Enterprise box running SQL 2008 in a dev environment. We host the database on an IBM DS3300 iSCSI san. We have a database, approx 102GB, on one of the SAN's LUNs (a copy of our production stuff), which is on a raid 10, 10 drives (15k, SAS). When we run a report on this server, it takes over 66 seconds to run. On the production server (granted, more hardware plus db is hosted on an expensive Fiber EMC SAN), the same report only takes 5-10 seconds. Looking at some perfmon stats, it seems the disk is the issue. For instance, for the SQLServer:Wait stats, the Page IO latch waits spike up to ~950 waits per second, with the other stats staying at 0 (waiting on disk IO). On the QliSCSI Adapter Stats (QLogic HBAs), my Read Bytes per second hits ~118 million, or 118 MBps. Avg Read Queue Length hits ~200, % Disk Read Time/Disk Time hits ~24,000. I'm getting 1800 IOPS. >From what I can tell, we're saturating the iSCSI link here. I'm on a gigabit switch, so if I took 1000 Mbps/8 = 125 MBps. Overhead/other stuff is using the SAN, 118 MBps would pretty much be a limit here. Am I wrong in my thinking? Is there something else I should be looking at? Now, during my research I came across a recommendation to format the NTFS drive the DB is on have an allocation size of 64KB to match the extents. Currently I'm at the default 4KB. Would this make much of a difference? I wanted to run this by some people who know more than I before I talk to the bosses. Thanks for all your help. Seth ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
