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* RAID 0 not as fast as expected
@ 2006-09-14 18:05 Craig A. James <cjames@modgraph-usa.com>
0 siblings, 2 replies; 15+ messages in thread
From: Craig A. James @ 2006-09-14 18:05 UTC (permalink / raw)
To: pgsql-performance
I'm experiment with RAID, looking for an inexpensive way to boost performance. I bought 4 Seagate 7200.9 120 GB SATA drives and two SIIG dual-port SATA cards. (NB: I don't plan to run RAID 0 in production, probably RAID 10, so no need to comment on the failure rate of RAID 0.)
I used this raw serial-speed test:
time sh -c "dd if=/dev/zero of=./bigfile bs=8k count=1000000 && sync"
(unmount/remount)
time sh -c "dd if=./bigfile of=/dev/null bs=8k count=1000000 && sync"
Which showed that the RAID 0 4-disk array was almost exactly twice as fast as each disk individually. I expected 4X performance for a 4-disk RAID 0. My suspicion is that each of these budget SATA cards is bandwidth limited; they can't actually handle two disks simultaneously, and I'd need to get four separate SATA cards to get 4X performance (or a more expensive card such as the Areca someone mentioned the other day).
On the other hand, it "feels like" (using our application) the seek performance is quite a bit better, which I'd expect given my hypothesis about the SIIG cards. I don't have concrete benchmarks on seek speed.
Thanks,
Craig
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: RAID 0 not as fast as expected
@ 2006-09-14 18:36 Alan Hodgson <ahodgson@simkin.ca>
parent: Craig A. James <cjames@modgraph-usa.com>
1 sibling, 1 reply; 15+ messages in thread
From: Alan Hodgson @ 2006-09-14 18:36 UTC (permalink / raw)
To: pgsql-performance; +Cc: Craig A. James <cjames@modgraph-usa.com>
On Thursday 14 September 2006 11:05, "Craig A. James"
<cjames@modgraph-usa.com> wrote:
> I'm experiment with RAID, looking for an inexpensive way to boost
> performance. I bought 4 Seagate 7200.9 120 GB SATA drives and two SIIG
> dual-port SATA cards. (NB: I don't plan to run RAID 0 in production,
> probably RAID 10, so no need to comment on the failure rate of RAID 0.)
>
Are those PCI cards? If yes, it's just a bus bandwidth limit.
--
Alan
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: RAID 0 not as fast as expected
@ 2006-09-14 18:49 Joshua D. Drake <jd@commandprompt.com>
parent: Craig A. James <cjames@modgraph-usa.com>
1 sibling, 1 reply; 15+ messages in thread
From: Joshua D. Drake @ 2006-09-14 18:49 UTC (permalink / raw)
To: Craig A. James <cjames@modgraph-usa.com>; +Cc: pgsql-performance
Craig A. James wrote:
> I'm experiment with RAID, looking for an inexpensive way to boost
> performance. I bought 4 Seagate 7200.9 120 GB SATA drives and two SIIG
> dual-port SATA cards. (NB: I don't plan to run RAID 0 in production,
> probably RAID 10, so no need to comment on the failure rate of RAID 0.)
>
> I used this raw serial-speed test:
>
> time sh -c "dd if=/dev/zero of=./bigfile bs=8k count=1000000 && sync"
> (unmount/remount)
> time sh -c "dd if=./bigfile of=/dev/null bs=8k count=1000000 && sync"
>
> Which showed that the RAID 0 4-disk array was almost exactly twice as
> fast as each disk individually. I expected 4X performance for a 4-disk
> RAID 0. My suspicion is that each of these budget SATA cards is
I am assuming linux here, Linux software raid 0 is known not to be super
duper.
Secondly remember that there is overhead involved with using raid. The
direct correlation doesn't work.
Joshua D. Drake
>
--
=== The PostgreSQL Company: Command Prompt, Inc. ===
Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
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^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: RAID 0 not as fast as expected
@ 2006-09-14 21:35 Craig A. James <cjames@modgraph-usa.com>
parent: Alan Hodgson <ahodgson@simkin.ca>
0 siblings, 1 reply; 15+ messages in thread
From: Craig A. James @ 2006-09-14 21:35 UTC (permalink / raw)
To: Alan Hodgson <ahodgson@simkin.ca>; +Cc: pgsql-performance
Alan Hodgson wrote:
> On Thursday 14 September 2006 11:05, "Craig A. James"
> <cjames@modgraph-usa.com> wrote:
>> I'm experiment with RAID, looking for an inexpensive way to boost
>> performance. I bought 4 Seagate 7200.9 120 GB SATA drives and two SIIG
>> dual-port SATA cards. (NB: I don't plan to run RAID 0 in production,
>> probably RAID 10, so no need to comment on the failure rate of RAID 0.)
>>
>
> Are those PCI cards? If yes, it's just a bus bandwidth limit.
Ok, that makes sense.
One SATA disk = 52 MB/sec
4-disk RAID0 = 106 MB/sec
PCI at 33 MHz x 32 bits (4 bytes) = 132 MB/sec.
I guess getting to 80% of the theoretical speed is as much as I should expect.
Thanks,
Craig
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: RAID 0 not as fast as expected
@ 2006-09-14 21:58 Scott Marlowe <smarlowe@g2switchworks.com>
parent: Craig A. James <cjames@modgraph-usa.com>
0 siblings, 0 replies; 15+ messages in thread
From: Scott Marlowe @ 2006-09-14 21:58 UTC (permalink / raw)
To: Craig A. James <cjames@modgraph-usa.com>; +Cc: Alan Hodgson <ahodgson@simkin.ca>; pgsql-performance
On Thu, 2006-09-14 at 16:35, Craig A. James wrote:
> Alan Hodgson wrote:
> > On Thursday 14 September 2006 11:05, "Craig A. James"
> > <cjames@modgraph-usa.com> wrote:
> >> I'm experiment with RAID, looking for an inexpensive way to boost
> >> performance. I bought 4 Seagate 7200.9 120 GB SATA drives and two SIIG
> >> dual-port SATA cards. (NB: I don't plan to run RAID 0 in production,
> >> probably RAID 10, so no need to comment on the failure rate of RAID 0.)
> >>
> >
> > Are those PCI cards? If yes, it's just a bus bandwidth limit.
>
> Ok, that makes sense.
>
> One SATA disk = 52 MB/sec
> 4-disk RAID0 = 106 MB/sec
>
> PCI at 33 MHz x 32 bits (4 bytes) = 132 MB/sec.
>
> I guess getting to 80% of the theoretical speed is as much as I should expect.
Note that many mid to high end motherboards have multiple PCI busses /
channels, and you could put a card in each one and get > 132MByte/sec on
them.
But for a database, sequential throughput is almost never the real
problem. It's usually random access that counts, and for that a RAID 10
is a pretty good choice.
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: RAID 0 not as fast as expected
@ 2006-09-15 03:36 Luke Lonergan <llonergan@greenplum.com>
parent: Joshua D. Drake <jd@commandprompt.com>
0 siblings, 1 reply; 15+ messages in thread
From: Luke Lonergan @ 2006-09-15 03:36 UTC (permalink / raw)
To: Joshua Drake <jd@commandprompt.com>; Craig A. James <cjames@modgraph-usa.com>; +Cc: pgsql-performance
Josh,
On 9/14/06 11:49 AM, "Joshua D. Drake" <jd@commandprompt.com> wrote:
> I am assuming linux here, Linux software raid 0 is known not to be super
> duper.
I've obtained 1,950 MB/s using Linux software RAID on SATA drives.
- Luke
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: RAID 0 not as fast as expected
@ 2006-09-15 03:47 Joshua D. Drake <jd@commandprompt.com>
parent: Luke Lonergan <llonergan@greenplum.com>
0 siblings, 1 reply; 15+ messages in thread
From: Joshua D. Drake @ 2006-09-15 03:47 UTC (permalink / raw)
To: Luke Lonergan <llonergan@greenplum.com>; +Cc: Craig A. James <cjames@modgraph-usa.com>; pgsql-performance
Luke Lonergan wrote:
> Josh,
>
> On 9/14/06 11:49 AM, "Joshua D. Drake" <jd@commandprompt.com> wrote:
>
>> I am assuming linux here, Linux software raid 0 is known not to be super
>> duper.
>
> I've obtained 1,950 MB/s using Linux software RAID on SATA drives.
With what? :)
>
> - Luke
>
>
--
=== The PostgreSQL Company: Command Prompt, Inc. ===
Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
Providing the most comprehensive PostgreSQL solutions since 1997
http://www.commandprompt.com/
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: RAID 0 not as fast as expected
@ 2006-09-15 03:51 Luke Lonergan <llonergan@greenplum.com>
parent: Joshua D. Drake <jd@commandprompt.com>
0 siblings, 1 reply; 15+ messages in thread
From: Luke Lonergan @ 2006-09-15 03:51 UTC (permalink / raw)
To: Joshua Drake <jd@commandprompt.com>; +Cc: Craig A. James <cjames@modgraph-usa.com>; pgsql-performance
Josh,
On 9/14/06 8:47 PM, "Joshua D. Drake" <jd@commandprompt.com> wrote:
>> I've obtained 1,950 MB/s using Linux software RAID on SATA drives.
>
> With what? :)
Sun X4500 (aka Thumper) running stock RedHat 4.3 (actually CentOS 4.3) with
XFS and the linux md driver without lvm. Here is a summary of the results:
Read Test
RAID Level Max Readahead (KB) RAID Chunksize Max Readahead on Disks (KB)
Max Time (s) Read Bandwidth (MB/s)
0 65536 64 256 16.689 1,917.43
0 4096 64 256 21.269 1,504.54
0 65536 256 256 17.967 1,781.04
0 2816 256 256 18.835 1,698.96
0 65536 1024 256 18.538 1,726.18
0 65536 64 512 18.295 1,749.11
0 65536 64 256 18.931 1,690.35
0 65536 64 256 18.873 1,695.54
0 64768 64 256 18.545 1,725.53
0 131172 64 256 18.548 1,725.25
0 131172 64 65536 19.046 1,680.14
0 131172 64 524288 18.125 1,765.52
0 131172 64 1048576 18.701 1,711.14
5 2560 64 256 39.933 801.34
5 16777216 64 256 37.76 847.46
5 524288 64 256 53.497 598.16
5 65536 32 256 38.472 831.77
5 65536 32 256 38.004 842.02
5 65536 32 256 37.884 844.68
5 2560 16 256 41.39 773.13
5 65536 16 256 48.902 654.37
10 65536 64 256 83.256 384.36
1+0 65536 64 256 19.394 1,649.99
1+0 65536 64 256 19.047 1,680.05
1+0 65536 64 256 19.195 1,667.10
1+0 65536 64 256 18.806 1,701.58
1+0 65536 64 256 18.848 1,697.79
1+0 65536 64 256 18.371 1,741.88
1+0 65536 64 256 21.446 1,492.12
1+0 65536 64 256 20.254 1,579.93
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: RAID 0 not as fast as expected
@ 2006-09-15 04:01 Joshua D. Drake <jd@commandprompt.com>
parent: Luke Lonergan <llonergan@greenplum.com>
0 siblings, 0 replies; 15+ messages in thread
From: Joshua D. Drake @ 2006-09-15 04:01 UTC (permalink / raw)
To: Luke Lonergan <llonergan@greenplum.com>; +Cc: Craig A. James <cjames@modgraph-usa.com>; pgsql-performance
Luke Lonergan wrote:
> Josh,
>
> On 9/14/06 8:47 PM, "Joshua D. Drake" <jd@commandprompt.com> wrote:
>
>>> I've obtained 1,950 MB/s using Linux software RAID on SATA drives.
>> With what? :)
>
> Sun X4500 (aka Thumper) running stock RedHat 4.3 (actually CentOS 4.3) with
> XFS and the linux md driver without lvm. Here is a summary of the results:
>
Good god!
>
> Read Test
> RAID Level Max Readahead (KB) RAID Chunksize Max Readahead on Disks (KB)
> Max Time (s) Read Bandwidth (MB/s)
> 0 65536 64 256 16.689 1,917.43
> 0 4096 64 256 21.269 1,504.54
> 0 65536 256 256 17.967 1,781.04
> 0 2816 256 256 18.835 1,698.96
> 0 65536 1024 256 18.538 1,726.18
> 0 65536 64 512 18.295 1,749.11
> 0 65536 64 256 18.931 1,690.35
> 0 65536 64 256 18.873 1,695.54
> 0 64768 64 256 18.545 1,725.53
> 0 131172 64 256 18.548 1,725.25
> 0 131172 64 65536 19.046 1,680.14
> 0 131172 64 524288 18.125 1,765.52
> 0 131172 64 1048576 18.701 1,711.14
> 5 2560 64 256 39.933 801.34
> 5 16777216 64 256 37.76 847.46
> 5 524288 64 256 53.497 598.16
> 5 65536 32 256 38.472 831.77
> 5 65536 32 256 38.004 842.02
> 5 65536 32 256 37.884 844.68
> 5 2560 16 256 41.39 773.13
> 5 65536 16 256 48.902 654.37
> 10 65536 64 256 83.256 384.36
> 1+0 65536 64 256 19.394 1,649.99
> 1+0 65536 64 256 19.047 1,680.05
> 1+0 65536 64 256 19.195 1,667.10
> 1+0 65536 64 256 18.806 1,701.58
> 1+0 65536 64 256 18.848 1,697.79
> 1+0 65536 64 256 18.371 1,741.88
> 1+0 65536 64 256 21.446 1,492.12
> 1+0 65536 64 256 20.254 1,579.93
>
>
--
=== The PostgreSQL Company: Command Prompt, Inc. ===
Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
Providing the most comprehensive PostgreSQL solutions since 1997
http://www.commandprompt.com/
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: RAID 0 not as fast as expected
@ 2006-09-15 12:43 Spiegelberg, Greg <gspiegelberg@cranel.com>
0 siblings, 1 reply; 15+ messages in thread
From: Spiegelberg, Greg @ 2006-09-15 12:43 UTC (permalink / raw)
To: Joshua D. Drake <jd@commandprompt.com>; Luke Lonergan <llonergan@greenplum.com>; +Cc: Craig A. James <cjames@modgraph-usa.com>; pgsql-performance
That's an all PCI-X box which makes sense. There are 6 SATA controllers
in that little beastie also. You can always count on Sun to provide
over engineered boxes.
> -----Original Message-----
> From: pgsql-performance-owner@postgresql.org
> [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of
> Joshua D. Drake
> Sent: Friday, September 15, 2006 12:01 AM
> To: Luke Lonergan
> Cc: Craig A. James; pgsql-performance@postgresql.org
> Subject: Re: [PERFORM] RAID 0 not as fast as expected
>
> Luke Lonergan wrote:
> > Josh,
> >
> > On 9/14/06 8:47 PM, "Joshua D. Drake" <jd@commandprompt.com> wrote:
> >
> >>> I've obtained 1,950 MB/s using Linux software RAID on SATA drives.
> >> With what? :)
> >
> > Sun X4500 (aka Thumper) running stock RedHat 4.3 (actually
> CentOS 4.3)
> > with XFS and the linux md driver without lvm. Here is a
> summary of the results:
> >
>
>
> Good god!
>
> >
> > Read Test
> > RAID Level Max Readahead (KB) RAID Chunksize Max Readahead
> on Disks
> > (KB) Max Time (s) Read Bandwidth (MB/s) 0 65536 64 256 16.689
> > 1,917.43 0 4096 64 256 21.269 1,504.54 0 65536 256 256 17.967
> > 1,781.04 0 2816 256 256 18.835 1,698.96 0 65536 1024 256 18.538
> > 1,726.18 0 65536 64 512 18.295 1,749.11 0 65536 64 256 18.931
> > 1,690.35 0 65536 64 256 18.873 1,695.54 0 64768 64 256 18.545
> > 1,725.53 0 131172 64 256 18.548 1,725.25 0 131172 64
> 65536 19.046
> > 1,680.14 0 131172 64 524288 18.125 1,765.52 0 131172 64 1048576
> > 18.701 1,711.14
> > 5 2560 64 256 39.933 801.34
> > 5 16777216 64 256 37.76 847.46
> > 5 524288 64 256 53.497 598.16
> > 5 65536 32 256 38.472 831.77
> > 5 65536 32 256 38.004 842.02
> > 5 65536 32 256 37.884 844.68
> > 5 2560 16 256 41.39 773.13
> > 5 65536 16 256 48.902 654.37
> > 10 65536 64 256 83.256 384.36
> > 1+0 65536 64 256 19.394 1,649.99
> > 1+0 65536 64 256 19.047 1,680.05
> > 1+0 65536 64 256 19.195 1,667.10
> > 1+0 65536 64 256 18.806 1,701.58
> > 1+0 65536 64 256 18.848 1,697.79
> > 1+0 65536 64 256 18.371 1,741.88
> > 1+0 65536 64 256 21.446 1,492.12
> > 1+0 65536 64 256 20.254 1,579.93
> >
> >
>
>
> --
>
> === The PostgreSQL Company: Command Prompt, Inc. ===
> Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
> Providing the most comprehensive PostgreSQL solutions since 1997
> http://www.commandprompt.com/
>
>
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 2: Don't 'kill -9' the postmaster
>
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: RAID 0 not as fast as expected
@ 2006-09-15 15:42 Luke Lonergan <llonergan@greenplum.com>
parent: Spiegelberg, Greg <gspiegelberg@cranel.com>
0 siblings, 1 reply; 15+ messages in thread
From: Luke Lonergan @ 2006-09-15 15:42 UTC (permalink / raw)
To: Spiegelberg, Greg <gspiegelberg@cranel.com>; Joshua Drake <jd@commandprompt.com>; +Cc: Craig A. James <cjames@modgraph-usa.com>; pgsql-performance
Greg, Josh,
Something I found out while doing this - lvm (and lvm2) slows the block
stream down dramatically. At first I was using it for convenience sake to
implement partitions on top of the md devices, but I found I was stuck at
about 700 MB/s. Removing lvm2 from the picture allowed me to get within
chucking distance of 2GB/s.
When we first started working with Solaris ZFS, we were getting about
400-600 MB/s, and after working with the Solaris Engineering team we now get
rates approaching 2GB/s. The updates needed to Solaris are part of the
Solaris 10 U3 available in October (and already in Solaris Express, aka
Solaris 11).
- Luke
On 9/15/06 5:43 AM, "Spiegelberg, Greg" <gspiegelberg@cranel.com> wrote:
> That's an all PCI-X box which makes sense. There are 6 SATA controllers
> in that little beastie also. You can always count on Sun to provide
> over engineered boxes.
>
>
>
>> -----Original Message-----
>> From: pgsql-performance-owner@postgresql.org
>> [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of
>> Joshua D. Drake
>> Sent: Friday, September 15, 2006 12:01 AM
>> To: Luke Lonergan
>> Cc: Craig A. James; pgsql-performance@postgresql.org
>> Subject: Re: [PERFORM] RAID 0 not as fast as expected
>>
>> Luke Lonergan wrote:
>>> Josh,
>>>
>>> On 9/14/06 8:47 PM, "Joshua D. Drake" <jd@commandprompt.com> wrote:
>>>
>>>>> I've obtained 1,950 MB/s using Linux software RAID on SATA drives.
>>>> With what? :)
>>>
>>> Sun X4500 (aka Thumper) running stock RedHat 4.3 (actually
>> CentOS 4.3)
>>> with XFS and the linux md driver without lvm. Here is a
>> summary of the results:
>>>
>>
>>
>> Good god!
>>
>>>
>>> Read Test
>>> RAID Level Max Readahead (KB) RAID Chunksize Max Readahead
>> on Disks
>>> (KB) Max Time (s) Read Bandwidth (MB/s) 0 65536 64 256 16.689
>>> 1,917.43 0 4096 64 256 21.269 1,504.54 0 65536 256 256 17.967
>>> 1,781.04 0 2816 256 256 18.835 1,698.96 0 65536 1024 256 18.538
>>> 1,726.18 0 65536 64 512 18.295 1,749.11 0 65536 64 256 18.931
>>> 1,690.35 0 65536 64 256 18.873 1,695.54 0 64768 64 256 18.545
>>> 1,725.53 0 131172 64 256 18.548 1,725.25 0 131172 64
>> 65536 19.046
>>> 1,680.14 0 131172 64 524288 18.125 1,765.52 0 131172 64 1048576
>>> 18.701 1,711.14
>>> 5 2560 64 256 39.933 801.34
>>> 5 16777216 64 256 37.76 847.46
>>> 5 524288 64 256 53.497 598.16
>>> 5 65536 32 256 38.472 831.77
>>> 5 65536 32 256 38.004 842.02
>>> 5 65536 32 256 37.884 844.68
>>> 5 2560 16 256 41.39 773.13
>>> 5 65536 16 256 48.902 654.37
>>> 10 65536 64 256 83.256 384.36
>>> 1+0 65536 64 256 19.394 1,649.99
>>> 1+0 65536 64 256 19.047 1,680.05
>>> 1+0 65536 64 256 19.195 1,667.10
>>> 1+0 65536 64 256 18.806 1,701.58
>>> 1+0 65536 64 256 18.848 1,697.79
>>> 1+0 65536 64 256 18.371 1,741.88
>>> 1+0 65536 64 256 21.446 1,492.12
>>> 1+0 65536 64 256 20.254 1,579.93
>>>
>>>
>>
>>
>> --
>>
>> === The PostgreSQL Company: Command Prompt, Inc. ===
>> Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
>> Providing the most comprehensive PostgreSQL solutions since 1997
>> http://www.commandprompt.com/
>>
>>
>>
>> ---------------------------(end of
>> broadcast)---------------------------
>> TIP 2: Don't 'kill -9' the postmaster
>>
>
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: RAID 0 not as fast as expected
@ 2006-09-15 18:28 Bucky Jordan <bjordan@lumeta.com>
parent: Luke Lonergan <llonergan@greenplum.com>
0 siblings, 1 reply; 15+ messages in thread
From: Bucky Jordan @ 2006-09-15 18:28 UTC (permalink / raw)
To: Luke Lonergan <llonergan@greenplum.com>; Spiegelberg, Greg <gspiegelberg@cranel.com>; Joshua Drake <jd@commandprompt.com>; +Cc: Craig A. James <cjames@modgraph-usa.com>; pgsql-performance
>When we first started working with Solaris ZFS, we were getting about
>400-600 MB/s, and after working with the Solaris Engineering team we
now >get
>rates approaching 2GB/s. The updates needed to Solaris are part of the
>Solaris 10 U3 available in October (and already in Solaris Express, aka
>Solaris 11).
Luke,
What other file systems have you had good success with? Solaris would be
nice, but it looks like I'm stuck running on FreeBSD (6.1, amd64) so
UFS2 would be the default. Not sure about XFS on BSD, and I'm not sure
at the moment that ext2/3 provide enough benefit over UFS to spend much
time on.
Also, has anyone had any experience with gmirror (good or bad)? I'm
thinking of trying to use it to stripe two hardware mirrored sets since
HW RAID10 wasn't doing as well as I had hoped (Dell Perc5/I controller).
For a 4 disk RAID 10 (10k rpm SAS/SCSI disks) what would be a good
target performance number? Right now, dd shows 224 MB/s.
And lastly, for a more OLAP style database, would I be correct in
assuming that sequential access speed would be more important than is
normally the case? (I have a relatively small number of connections, but
each running on pretty large data sets).
Thanks,
Bucky
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: RAID 0 not as fast as expected
@ 2006-09-16 23:46 Luke Lonergan <llonergan@greenplum.com>
parent: Bucky Jordan <bjordan@lumeta.com>
0 siblings, 1 reply; 15+ messages in thread
From: Luke Lonergan @ 2006-09-16 23:46 UTC (permalink / raw)
To: Bucky Jordan <bjordan@lumeta.com>; Spiegelberg, Greg <gspiegelberg@cranel.com>; Joshua Drake <jd@commandprompt.com>; +Cc: Craig A. James <cjames@modgraph-usa.com>; pgsql-performance
Bucky,
On 9/15/06 11:28 AM, "Bucky Jordan" <bjordan@lumeta.com> wrote:
> What other file systems have you had good success with? Solaris would be
> nice, but it looks like I'm stuck running on FreeBSD (6.1, amd64) so
> UFS2 would be the default. Not sure about XFS on BSD, and I'm not sure
> at the moment that ext2/3 provide enough benefit over UFS to spend much
> time on.
It won't matter much between UFS2 or others until you get past about 350
MB/s.
> Also, has anyone had any experience with gmirror (good or bad)? I'm
> thinking of trying to use it to stripe two hardware mirrored sets since
> HW RAID10 wasn't doing as well as I had hoped (Dell Perc5/I controller).
> For a 4 disk RAID 10 (10k rpm SAS/SCSI disks) what would be a good
> target performance number? Right now, dd shows 224 MB/s.
Each disk should sustain somewhere between 60-80 MB/s (see
http://www.storagereview.com/ for a profile of your disk).
Your dd test sounds suspiciously too fast unless you were running two
simultaneous dd processes. Did you read from a file that was at least twice
the size of RAM?
A single dd stream would run between 120 and 160 MB/s on a RAID10, two
streams would be between 240 and 320 MB/s.
> And lastly, for a more OLAP style database, would I be correct in
> assuming that sequential access speed would be more important than is
> normally the case? (I have a relatively small number of connections, but
> each running on pretty large data sets).
Yes. What's pretty large? We've had to redefine large recently, now we're
talking about systems with between 100TB and 1,000TB.
- Luke
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: RAID 0 not as fast as expected
@ 2006-09-17 00:08 Steinar H. Gunderson <sgunderson@bigfoot.com>
parent: Luke Lonergan <llonergan@greenplum.com>
0 siblings, 1 reply; 15+ messages in thread
From: Steinar H. Gunderson @ 2006-09-17 00:08 UTC (permalink / raw)
To: pgsql-performance
On Sat, Sep 16, 2006 at 04:46:04PM -0700, Luke Lonergan wrote:
> Yes. What's pretty large? We've had to redefine large recently, now we're
> talking about systems with between 100TB and 1,000TB.
Do you actually have PostgreSQL databases in that size range?
/* Steinar */
--
Homepage: http://www.sesse.net/
^ permalink raw reply [nested|flat] 15+ messages in thread
* Re: RAID 0 not as fast as expected
@ 2006-09-17 00:44 Joshua D. Drake <jd@commandprompt.com>
parent: Steinar H. Gunderson <sgunderson@bigfoot.com>
0 siblings, 0 replies; 15+ messages in thread
From: Joshua D. Drake @ 2006-09-17 00:44 UTC (permalink / raw)
To: pgsql-performance
Steinar H. Gunderson wrote:
> On Sat, Sep 16, 2006 at 04:46:04PM -0700, Luke Lonergan wrote:
>> Yes. What's pretty large? We've had to redefine large recently, now we're
>> talking about systems with between 100TB and 1,000TB.
>
> Do you actually have PostgreSQL databases in that size range?
No, they have databases in MPP that are that large :)
Joshua D. Drake
>
> /* Steinar */
--
=== The PostgreSQL Company: Command Prompt, Inc. ===
Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
Providing the most comprehensive PostgreSQL solutions since 1997
http://www.commandprompt.com/
^ permalink raw reply [nested|flat] 15+ messages in thread
end of thread, other threads:[~2006-09-17 00:44 UTC | newest]
Thread overview: 15+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2006-09-14 18:05 RAID 0 not as fast as expected Craig A. James <cjames@modgraph-usa.com>
2006-09-14 18:36 ` Alan Hodgson <ahodgson@simkin.ca>
2006-09-14 21:35 ` Craig A. James <cjames@modgraph-usa.com>
2006-09-14 21:58 ` Scott Marlowe <smarlowe@g2switchworks.com>
2006-09-14 18:49 ` Joshua D. Drake <jd@commandprompt.com>
2006-09-15 03:36 ` Luke Lonergan <llonergan@greenplum.com>
2006-09-15 03:47 ` Joshua D. Drake <jd@commandprompt.com>
2006-09-15 03:51 ` Luke Lonergan <llonergan@greenplum.com>
2006-09-15 04:01 ` Joshua D. Drake <jd@commandprompt.com>
2006-09-15 12:43 Re: RAID 0 not as fast as expected Spiegelberg, Greg <gspiegelberg@cranel.com>
2006-09-15 15:42 ` Luke Lonergan <llonergan@greenplum.com>
2006-09-15 18:28 ` Bucky Jordan <bjordan@lumeta.com>
2006-09-16 23:46 ` Luke Lonergan <llonergan@greenplum.com>
2006-09-17 00:08 ` Steinar H. Gunderson <sgunderson@bigfoot.com>
2006-09-17 00:44 ` Joshua D. Drake <jd@commandprompt.com>
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