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Slow SSD in DL380 G8

kikky69
Occasional Visitor

Slow SSD in DL380 G8

Hi Guys,

 

i've have a problem with slow SSDs on a DL380 g8.

 

There are 2 HDDs à 300 GB built in and 2 SSDs (200 GB; original HP). The Controller is a P410i with 1 GB. The HDD are configured in an Array and the SSD also (Mirroring).

The installed OS is Debian 7/64.

 

The resutl of

dd if=/dev/zero of=tempfile bs=1M count=1024 conv=fdatasync,notrunc

 

is on the HDD 488 mb/s an on the SDD 235 m/s.

 

What do you think is causing the problem? What can I do? Any suggestions?

Kind regards

 

 

4 REPLIES
Jimmy Vance
HPE Pro

Re: Slow SSD in DL380 G8

What model are the HDD's and what model are the SDD's If the SDD's are the 200 GB SATA drives, I think they are spec'd at 235 MiB/s




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kikky69
Occasional Visitor

Re: Slow SSD in DL380 G8

Hi Jimmy,

 

the SSD Model is: HPEO0200FBRW. It is a SAS-Drive; the HDDs are EG0300FCVBF  - SAS; 10K.

 

I found out that the issue has to do with the alignment of the SSDs. I've tried a lot of different things - but the performance of the diks is poor.

 

I studied a lot of papers an tips in the net, but i havn't a solution yet. The installed OS is debian. I formatted the disks with fdsik as described here http://tytso.livejournal.com/tag/ssd.

 

But that did not work really. Do you've got a idea what i can do?

johnsmm
Occasional Visitor

Re: Slow SSD in DL380 G8

I have same issue.

I have DL380p Gen8 with P830 controller that has 4GB cache and battery using HGST 800GB SSD SAS drive.
With SSD Smart path turned on im getting 340 mb/s reads
With SSD Smart path off and caching on getting 190 mb/s

When i plug that same drive into old IBM server i get 600mb/s reads out of the box.

All the tests were done in Crystal Disk Benchmark using 8GB test mode (to make sure its not using controllers cache)

Tried ESXi 6.0 and 6.5 with all updated firmwares and all updated drivers. 

 

iotflash
Frequent Visitor

Re: Slow SSD in DL380 G8

As I understand, for SSD, read and write performance are quite different. Normally, the read performance is fairly consistent but the write performance. For example, if the SSD is brand new, the write performance is pretty high. When it has been written, particularilly, it has been written with random data, the write and mixed write/read performance will drop significantly due to garbage collection insight of the SSD.