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Home > Archive > Data Storage > June 2004 > Very poor performance of Serial ATA (Dell/EMC)
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Very poor performance of Serial ATA (Dell/EMC)
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| Rick Denoire 2004-06-01, 5:06 pm |
| Hello
I am using a storage system from Dell/EMC CX-400 with two DAEs (two
cases to fill in harddisks). One case is full with FC Seagate 15K 36GB
harddisks. I have never been enthusiastic about its performance but at
least it seems that you can operate an Oracle DB on these disks.
The secound case has 10 S-ATA disks, 250 GB each. It strikes me that I
never get a transfer rate of more than 4 MB/sec when copying large
files of more than 2 GB (which are mostly in one chunk, i.e.
unfragmented). I mean copying them locally on the same host.
Well, I am engaged trying to use the advances capabilities of this
device. The CX-400 is at the heart of a Fibre Channel SAN where
several Linux and Solaris machines are connected to. By detaching a
LUN from one host and attaching it to another (of the same platform)
one should be able to do mass data copy without having to go through
the network.
Well but at 4 MB/sec, the network is faster (1 GB Ethernet).
According to Dell, the typical sustained transfer rate is about 30
MB/sec for the Serial ATA disks. Please see the article at:
http://www1.us.dell.com/content/top...=555&l=en&s=biz
What should I look at when investigating these performance issues?
What are your experiences?
Thanks
Rick Denoire
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| Xiaozhou Qiu 2004-06-02, 12:02 am |
| Rick,
The number you gave, 4MB/sec, seems to be like raw disk I/O speed.
Probaby you did not turn on the write cache. You may need to enable it
on the client side. i.e. Windows often disable write cache by default
and you have to manually enable it in disk manager. Sometimes you may
need to go to the storage and force enabliing write cache to improve
the performance.
Leo Qiu
Rick Denoire <100.17706@germanynet.de> wrote in message news:<d9jpb0lrc3d1incld47u23vhjduftl7op4@4ax.com>...
> Hello
>
> I am using a storage system from Dell/EMC CX-400 with two DAEs (two
> cases to fill in harddisks). One case is full with FC Seagate 15K 36GB
> harddisks. I have never been enthusiastic about its performance but at
> least it seems that you can operate an Oracle DB on these disks.
>
> The secound case has 10 S-ATA disks, 250 GB each. It strikes me that I
> never get a transfer rate of more than 4 MB/sec when copying large
> files of more than 2 GB (which are mostly in one chunk, i.e.
> unfragmented). I mean copying them locally on the same host.
>
> Well, I am engaged trying to use the advances capabilities of this
> device. The CX-400 is at the heart of a Fibre Channel SAN where
> several Linux and Solaris machines are connected to. By detaching a
> LUN from one host and attaching it to another (of the same platform)
> one should be able to do mass data copy without having to go through
> the network.
>
> Well but at 4 MB/sec, the network is faster (1 GB Ethernet).
>
> According to Dell, the typical sustained transfer rate is about 30
> MB/sec for the Serial ATA disks. Please see the article at:
>
> http://www1.us.dell.com/content/top...=555&l=en&s=biz
>
> What should I look at when investigating these performance issues?
> What are your experiences?
>
> Thanks
> Rick Denoire
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| - C - 2004-06-02, 12:03 am |
| Check out a benchmark for a SATA adaptor at
http://www.xbitlabs.com/articles/st...tec-2410sa.html
They can get 120mb/s with a 3 disk raid0 or 6 disk raid10. Even my desktop
ide drive can do 30mb/s...
RAW SATA disk I/O should be around 35mb/s, checkout EMC's own website
"Xiaozhou Qiu" <xzqiu@hotmail.com> wrote in message
news:22556a72.0406011531.7d0f6c49@posting.google.com...
> Rick,
>
> The number you gave, 4MB/sec, seems to be like raw disk I/O speed.
> Probaby you did not turn on the write cache. You may need to enable it
> on the client side. i.e. Windows often disable write cache by default
> and you have to manually enable it in disk manager. Sometimes you may
> need to go to the storage and force enabliing write cache to improve
> the performance.
>
> Leo Qiu
>
> Rick Denoire <100.17706@germanynet.de> wrote in message
news:<d9jpb0lrc3d1incld47u23vhjduftl7op4@4ax.com>...[vbcol=seagreen]
http://www1.us.dell.com/content/top...=555&l=en&s=biz[vbcol=seagreen]
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