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Performance problem SAS 300 Go/E200/DL380G5

gatouillat
Occasional Advisor

Performance problem SAS 300 Go/E200/DL380G5

Hi,

I have a DL380G5 with 2 hdd 36 GB SAS / RAID-1 for system and 2 hdd 300 GB SAS / RAID-1 for data, in internal storage enclosure on the E200 integrated controller/64 MB of cache (100% READ, 0% WRITE, no way to change that). I have also an MSA20 with 12 hdd 500 Go SATA connected through a P6400 (no problem with it)

The write performances on the data partition (with 300 GB HDD) are very poor, max. of 9 MBytes/s, average 6 MB/s, for a file of several Giga, that I copy from the MSA20. The read performance are good, max. of 60 MB/s.

Is this due to the E200 controller ?
Otherwise how can I investigate to find where is the problem ?

No specific load on CPU.

HDD 300 GB : HP DG0300BALVP - firmware HPD2 - 10k RPM

DATA RAID-1 stripe size 128kB

Thanks,
Pierre
4 REPLIES
gatouillat
Occasional Advisor

Re: Performance problem SAS 300 Go/E200/DL380G5

Forget to give the firmware of E200i : 1.84
TTr
Honored Contributor

Re: Performance problem SAS 300 Go/E200/DL380G5

> E200 integrated controller/64 MB of cache (100% READ, 0% WRITE, no way to change that).

Having write cache make a big difference in the write performance. Why "no way to change that"?

> MSA20 with 12 hdd 500GB SATA connected through a P6400 (no problem with it)

Why do you say there is no problem in the MSA20? How are the 12 disks configured in it? If all 12 disks are one single raid array, then the 6400 has to read all 12 disks to get a single stripe out and serve data. And they are SATA 1.5Gb each and they have to convert to a SCSI interface, so there is a conversion overhead as well.

You can test by copying from the 36GB diks to the 300Gb disks to see if the problem is in the E200 or the 6402/MSA20.

You should look into using the iozone tool for some i/o performance benchmarks.
gatouillat
Occasional Advisor

Re: Performance problem SAS 300 Go/E200/DL380G5

>> E200 integrated controller/64 MB of cache (100% READ, 0% WRITE, no way to change that).

>Having write cache make a big difference in the write performance. Why "no way to change that"?

Because with only 64 MB of cache, there is no possibility to change value between Read an Write in the ACU

>> MSA20 with 12 hdd 500GB SATA connected through a P6400 (no problem with it)

>Why do you say there is no problem in the MSA20? How are the 12 disks configured in it? If all 12 disks are one single raid array, then the 6400 has to read all 12 disks to get a single stripe out and serve data. And they are SATA 1.5Gb each and they have to convert to a SCSI interface, so there is a conversion overhead as well.

When I copy from DATA partition to MSA20, I have good performance (50-60 MB/s), so I think there is no problem with MSA20

>You can test by copying from the 36GB diks to the 300Gb disks to see if the problem is in the E200 or the 6402/MSA20.

Same performance from 36 GB to 300 GB or 300 to 36, about 6-8 MB/s

Other tests I done : copy on the same partition 300 GB, about 6-8 MB/s ; copy on the same partition 36 GB, about 4-5 MB/s

I think I have a problem with the E200 or not enough cache because on another server with 300 GB SCSI disk and smartarray 6i/192 MB cache, I have good performance (50-60 MB/s in writing)
u84823
Regular Advisor

Re: Performance problem SAS 300 Go/E200/DL380G5

You need the battery-backed write cache upgrade for the board, HP P/N 346914-B21, this will provide a *dramatic* improvement to write speeds.