|
Home > Archive > MS SQL Server > December 2006 > Slow hard disk?
You are viewing an archived Text-only version of the thread.
To view this thread in it's original format and/or if you want to reply to
this thread please [click here]
|
|
|
| I have a dual cpu server, windows 2000, 4G memory, RAID 5 hard disk array
The server is very slow,
Avg. Disk Bytes/Read 47xxx.xxx
Avg. Disk Read Queue Length 78.xxx
Avg. Disk sec/Read 1.7xx
Disk Read Bytes/sec 2M
Disk Reads/sec 25.xxx
SQL Server Active transaction 1
The CPU usage is quite low. 99% idle.
Any problem with the hard disk according to the stat?
Tia.
| |
| Tracy McKibben 2006-12-05, 7:12 pm |
| nkw wrote:
> I have a dual cpu server, windows 2000, 4G memory, RAID 5 hard disk array
>
> The server is very slow,
> Avg. Disk Bytes/Read 47xxx.xxx
> Avg. Disk Read Queue Length 78.xxx
> Avg. Disk sec/Read 1.7xx
> Disk Read Bytes/sec 2M
> Disk Reads/sec 25.xxx
> SQL Server Active transaction 1
>
> The CPU usage is quite low. 99% idle.
>
> Any problem with the hard disk according to the stat?
>
> Tia.
>
>
My initial response would be yes, your drive array seems to be overloaded.
--
Tracy McKibben
MCDBA
http://www.realsqlguy.com
| |
| Tom Moreau 2006-12-05, 7:12 pm |
| The disk read queue length looks very high. (Your disk is a bottleneck.)
I'd also look at adding memory, if you are using Advanced Server. If not,
try setting the /3GB switch in BOOT.INI.
--
Tom
----------------------------------------------------
Thomas A. Moreau, BSc, PhD, MCSE, MCDBA, MCITP, MCTS
SQL Server MVP
Toronto, ON Canada
..
"nkw" <nkw@discussions.microsoft.com> wrote in message
news:F1BE162D-F62D-42AE-B3FC- E8E1D0416367@microso
ft.com...
I have a dual cpu server, windows 2000, 4G memory, RAID 5 hard disk array
The server is very slow,
Avg. Disk Bytes/Read 47xxx.xxx
Avg. Disk Read Queue Length 78.xxx
Avg. Disk sec/Read 1.7xx
Disk Read Bytes/sec 2M
Disk Reads/sec 25.xxx
SQL Server Active transaction 1
The CPU usage is quite low. 99% idle.
Any problem with the hard disk according to the stat?
Tia.
| |
|
| I am SS standard edition, can it use /3GB?
tx
"Tom Moreau" wrote:
> The disk read queue length looks very high. (Your disk is a bottleneck.)
> I'd also look at adding memory, if you are using Advanced Server. If not,
> try setting the /3GB switch in BOOT.INI.
>
> --
> Tom
>
> ----------------------------------------------------
> Thomas A. Moreau, BSc, PhD, MCSE, MCDBA, MCITP, MCTS
> SQL Server MVP
> Toronto, ON Canada
> ..
> "nkw" <nkw@discussions.microsoft.com> wrote in message
> news:F1BE162D-F62D-42AE-B3FC- E8E1D0416367@microso
ft.com...
> I have a dual cpu server, windows 2000, 4G memory, RAID 5 hard disk array
>
> The server is very slow,
> Avg. Disk Bytes/Read 47xxx.xxx
> Avg. Disk Read Queue Length 78.xxx
> Avg. Disk sec/Read 1.7xx
> Disk Read Bytes/sec 2M
> Disk Reads/sec 25.xxx
> SQL Server Active transaction 1
>
> The CPU usage is quite low. 99% idle.
>
> Any problem with the hard disk according to the stat?
>
> Tia.
>
>
>
| |
|
| Btw, is the "Disk Read Bytes/sec" too low for RAID 5? It's only 2M.
"nkw" wrote:
> I have a dual cpu server, windows 2000, 4G memory, RAID 5 hard disk array
>
> The server is very slow,
> Avg. Disk Bytes/Read 47xxx.xxx
> Avg. Disk Read Queue Length 78.xxx
> Avg. Disk sec/Read 1.7xx
> Disk Read Bytes/sec 2M
> Disk Reads/sec 25.xxx
> SQL Server Active transaction 1
>
> The CPU usage is quite low. 99% idle.
>
> Any problem with the hard disk according to the stat?
>
> Tia.
>
>
| |
| Arnie Rowland 2006-12-05, 7:12 pm |
| Yes.
It appears that this may be a write intensive database. RAID 5 is not a good
choice. RAID 10 would be a great improvement.
Also, do you have the TLog on the same RAID5 array?
Is there any chance that the TempDb is also on the same RAID5 array?
--
Arnie Rowland, Ph.D.
Westwood Consulting, Inc
Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous
You can't help someone get up a hill without getting a little closer to the
top yourself.
- H. Norman Schwarzkopf
"nkw" <nkw@discussions.microsoft.com> wrote in message
news:156BD28C-58CE-4D0C-BA97- 0CC12500B7D7@microso
ft.com...[color=darkred]
>I am SS standard edition, can it use /3GB?
>
> tx
>
> "Tom Moreau" wrote:
>
| |
| Linchi Shea 2006-12-06, 12:12 am |
| Your disk performance is absolutely abysmal. The tell-tale sign is Avg. Disk
sec/Read. With a value of 1.7 sec for this counter, the disk (or disk array)
is practically not usable (in this state anyway). Also, 25 Disk Reads/sec for
an average of about 40KB per read is very bad.
With disk performance like this, it's not surprising that the CPU usage is
so low because the computer is spending most of its time waiting for I/O to
complete.
For the I/O sizes indicated in your posted sample, any time you see the
value of Avg Disk sec/Read greater than 20ms for any sustained time period,
your storage I/O is beyond bad.
Linchi
"nkw" wrote:
> I have a dual cpu server, windows 2000, 4G memory, RAID 5 hard disk array
>
> The server is very slow,
> Avg. Disk Bytes/Read 47xxx.xxx
> Avg. Disk Read Queue Length 78.xxx
> Avg. Disk sec/Read 1.7xx
> Disk Read Bytes/sec 2M
> Disk Reads/sec 25.xxx
> SQL Server Active transaction 1
>
> The CPU usage is quite low. 99% idle.
>
> Any problem with the hard disk according to the stat?
>
> Tia.
>
>
|
|
|
|
|