DL380 G3 Disk I/O Problem

[Martin Harrow_1]

I have a DL380 G3 (2Gb,3.06GHz,Smart Array 5i, Windows 2000 Server SP4, 100Mbps FD NIC) with 6 x 146Gb disks set up as 1 RAID 5 array.
Server speed is good, but when the disks are under high read/write strain, file access is very slow, and the server drops network connections. If I use performance monitor, the disk throughput is between 1 and 5 Mb/sec.The queue length though varies between 20 aand 40.
I want to keep the Smart Array 5i, but realise that this queue length is too high. Would the addition of a write cache enabler chip help me?

[Oleg Koroz]

Positively: read - write 50/50 128mb or 256mb write cache enabled can help you (not sure if Compaq make 256MB for 5i, if not 5300 controller should support 256mb)

[Luis Valencia]

I would like to contribute clarifying a couple of things.

First, the Smart Array 5i has no batteries for cache, so what you have is read cache, not write cache.

In order to have write cahce you'll need a 5i+ or a 6i+ with BBWC Enabler.

Second, installing Windows 2000 or 2003 in RAID 5 is not the best scenario. Remember that the page file writes constantly (it is part of RAM), so you are calculating parity for every memory write to disk.

I would recommend to use a RAID controller as KOV mentioned (but 5300 are EOL) now is 6400 with battery backed cache memory and if possibly, migrate your Windows system disk to RAID 1, to get the best write performance.

Luis

[Scott_59]

I think it would be helpful to take into consideration what software is installed on this server too.

Are all the drives one huge partition? If so is the OS installed on the same partition along with applications? Also if there is one partition does that partition have array intensive activity - ie a database? What is the paging file set to?

Scott

[Martin Harrow_1]

Yes, OS and files are on the same RAID 5 partition, but the server is a file only server. There are no databases or applications running. Although some of the files are, of course, large!

Page File is on the OS drive, set to 5Gb.