poor scsi perfomance on ML370 G4 while indexing

[robinsolo]

My system : ML370 G4 + Linux red hat enterprise 4, 1 GB Memory, HDD 73 SCSI Hot plug x 3. The system perfomance very poor on indexing the database let say finish 57 minute, but when i used the IDE harddrive the perfomance very good, finist indexing only 7 minute. Can somebody help me about it ? I already update the BIOS but no help at all

[Rob Leadbeater]

Hi,

I suspect that you're using a SmartArray controller without the Battery Backed Write Cache option.

Without the BBWC, performance of SmartArray controllers can be very slow.

Cheers,

Rob

[robinsolo]

Hi Rob,

I use Smartarray 642, can you tell me more about backed battery write option ?

Tx

[Samnang]

Hi,

Usually SA642 come with 64MB of BBWC, you can upgrate to Max (192MB) with this kit

BBWC Enabler Options
128-MB BBWC (Battery-Backed Write Cache) Enabler

351580-B21

Regard,

[Igor Karasik]

>>I use Smartarray 642, can you tell me more about backed battery write option ?

SmartArray 642 have 64 Mb read cache memory
and you can add 64 Mb or 128 Mb Battery Backed Write Cache

http://h18004.www1.hp.com/products/servers/proliantstorage/arraycontrollers/smartarray642/index.html?jumpid=reg_R1002_USEN
"The 64MB and 128MB BBWC (Battery Backed Write Cache) Enabler upgrade allows the SA-642 controller an option to add transportable BBWC for improved controller performance and increases the total controller memory, up to 192MB."
http://h18004.www1.hp.com/products/quickspecs/12069_div/12069_div.html

PROBABLY write cache will improve performance, I am not sure if you will have significant improvement in database indexing

[raadek]

Are you using RAID5? I guess so looking at the number of hard drives.

RAID5 has very large performance overhead - especially for random writes (e.g. databases). When you do not have write chache it could be much slower than a single drive.

You will benefit a lot from adding one more HDD and migrating to RAID10 in the terms of performance!

Still adding BBWC seems to be almost a necessity if you are after a decent speed.

Rgds.

[robinsolo]

Hi All,

Is it BBWC enable by default ? or we must enable it ? When I look the SA642 there's no memory at all at the slot. Is it sale saparetly ?

I already tried a single disk (SCSI) but still much slower compare with single disk (IDE). How come ?

Regards,

Robinsolo