Read-Ahead Cache Limit

[Ayman Altounji]

Hi
Running a CL380 with Windows 2000 Advanced Server SP2 and Exchange 5.5. Each node as 1.5Gb of memory and the storage in the CL380 is configured as RAID5 plus spare. I have attached a Storage 4214 unit so that the Exchange transaction logs are on a separate mirrored drives. We are seeing intermittant performance problems. I was wondering what the correct read-ahead cache limit setting should be for a CR3500 with external storage attached.
Thanks

[Ayman Altounji]

Read ahead cache will help with sequential data reads but will not help with random reads. For Exchange this would mean if the messages have a lot of attachments which are frequently opened or the messages themselves are large, then setting the read ahead cache would help.
We have seen some performance issues related to CR3500 controller firmware and SCSI drivers, so we recommend that customer use firmware version x2r-1 (available at <>
and the SCSI HBA driver from SmartStart 5.20 or later.
Thanks

[Ayman Altounji]

Installed the firmware upgrade and moved to 5.30 smart start. Initial signs are that the problem is now resolved.
Thanks