Thread: Re: [PATCHES] COPY FROM performance improvements
Here is the SCSI output: Web Server SCSI subsystem driver Revision: 1.00 megaraid: v1.18j (Release Date: Mon Jul 7 14:39:55 EDT 2003) megaraid: found 0x1028:0x000f:idx 0:bus 4:slot 3:func 0 scsi0 : Found a MegaRAID controller at 0xf883f000, IRQ: 18 scsi0 : Enabling 64 bit support megaraid: [412W:H406] detected 1 logical drives megaraid: supports extended CDBs. megaraid: channel[1] is raid. megaraid: channel[2] is raid. scsi0 : LSI Logic MegaRAID 412W 254 commands 15 targs 5 chans 7 luns Database Server SCSI subsystem driver Revision: 1.00 megaraid: v1.18j (Release Date: Mon Jul 7 14:39:55 EDT 2003) megaraid: found 0x101e:0x1960:idx 0:bus 5:slot 0:func 0 scsi0 : Found a MegaRAID controller at 0xf883f000, IRQ: 21 scsi0 : Enabling 64 bit support megaraid: [196T:3.33] detected 1 logical drives megaraid: supports extended CDBs. megaraid: channel[1] is raid. megaraid: channel[2] is raid. scsi0 : LSI Logic MegaRAID 196T 254 commands 15 targs 5 chans 7 luns Starting timer : 0 0 blk: queue c5f2d218, I/O limit 4095Mb (mask 0xffffffff) scsi0: scanning virtual channel 0 for logical drives. Vendor: MegaRAID Model: LD 0 RAID5 86G Rev: 196T Type: Direct-Access ANSI SCSI revision: 02 Starting timer : 0 0 The webserver is a 1U and it actually performs better on the IO than the database server even though the database server is running 6 disks versus 3. The database server is a PE (Power Edge) 6600 Database Server IO: [root@master root]# /sbin/hdparm -tT /dev/sda /dev/sda: Timing buffer-cache reads: 1888 MB in 2.00 seconds = 944.00 MB/sec Timing buffered disk reads: 32 MB in 3.06 seconds = 10.46 MB/sec Second Database Server IO: [root@pq-slave root]# /sbin/hdparm -tT /dev/sda /dev/sda: Timing buffer-cache reads: 1816 MB in 2.00 seconds = 908.00 MB/sec Timing buffered disk reads: 26 MB in 3.11 seconds = 8.36 MB/sec [root@pq-slave root]# Which is just horrible. Sincerely, Joshua D. Drake Patrick Welche wrote: > On Thu, Jul 21, 2005 at 09:19:04PM -0700, Luke Lonergan wrote: > >>Joshua, >> >>On 7/21/05 7:53 PM, "Joshua D. Drake" <jd@commandprompt.com> wrote: >> >>>Well I know that isn't true at least not with ANY of the Dells my >>>customers have purchased in the last 18 months. They are still really, >>>really slow. >> >>That's too bad, can you cite some model numbers? SCSI? > > > I would be interested too, given > > http://www.netbsd.org/cgi-bin/query-pr-single.pl?number=30531 > > > Cheers, > > Patrick > > ---------------------------(end of broadcast)--------------------------- > TIP 4: Have you searched our list archives? > > http://archives.postgresql.org -- Your PostgreSQL solutions company - Command Prompt, Inc. 1.800.492.2240 PostgreSQL Replication, Consulting, Custom Programming, 24x7 support Managed Services, Shared and Dedicated Hosting Co-Authors: plPHP, plPerlNG - http://www.commandprompt.com/
Joshua, On 7/22/05 10:11 AM, "Joshua D. Drake" <jd@commandprompt.com> wrote: > The database server is a PE (Power Edge) 6600 > > Database Server IO: > > [root@master root]# /sbin/hdparm -tT /dev/sda > > /dev/sda: > Timing buffer-cache reads: 1888 MB in 2.00 seconds = 944.00 MB/sec > Timing buffered disk reads: 32 MB in 3.06 seconds = 10.46 MB/sec > > Second Database Server IO: > > [root@pq-slave root]# /sbin/hdparm -tT /dev/sda > > /dev/sda: > Timing buffer-cache reads: 1816 MB in 2.00 seconds = 908.00 MB/sec > Timing buffered disk reads: 26 MB in 3.11 seconds = 8.36 MB/sec > [root@pq-slave root]# Can you post the "time dd if=/dev/zero of=bigfile bs=8k count=500000" results? Also do the reverse (read the file) with "time dd if=bigfile of=/dev/null bs=8k". I think you are observing what we've known for a while, hardware RAID is horribly slow. We've not found a hardware RAID adapter of this class yet that shows reasonable read or write performance. The Adaptec 2400R or the LSI or others have terrible internal I/O compared to raw SCSI with software RAID, and even the CPU usage is higher on these cards while doing slower I/O than linux SW RAID. Notably - we've found that the 3Ware RAID controller does a better job than the low end SCSI RAID at HW RAID support, and also exports JBOD at high speeds. If you export JBOD on the low end SCSI RAID adapters, the performance is also very poor, though generally faster than using HW RAID. - Luke
On Fri, 22 Jul 2005 12:28:43 -0700 "Luke Lonergan" <llonergan@greenplum.com> wrote: > Joshua, > > On 7/22/05 10:11 AM, "Joshua D. Drake" <jd@commandprompt.com> wrote: > > The database server is a PE (Power Edge) 6600 > > > > Database Server IO: > > > > [root@master root]# /sbin/hdparm -tT /dev/sda > > > > /dev/sda: > > Timing buffer-cache reads: 1888 MB in 2.00 seconds = 944.00 MB/sec > > Timing buffered disk reads: 32 MB in 3.06 seconds = 10.46 MB/sec > > > > Second Database Server IO: > > > > [root@pq-slave root]# /sbin/hdparm -tT /dev/sda > > > > /dev/sda: > > Timing buffer-cache reads: 1816 MB in 2.00 seconds = 908.00 MB/sec > > Timing buffered disk reads: 26 MB in 3.11 seconds = 8.36 MB/sec > > [root@pq-slave root]# > > Can you post the "time dd if=/dev/zero of=bigfile bs=8k count=500000" > results? Also do the reverse (read the file) with "time dd if=bigfile > of=/dev/null bs=8k". > > I think you are observing what we've known for a while, hardware RAID is > horribly slow. We've not found a hardware RAID adapter of this class yet > that shows reasonable read or write performance. The Adaptec 2400R or the > LSI or others have terrible internal I/O compared to raw SCSI with software > RAID, and even the CPU usage is higher on these cards while doing slower I/O > than linux SW RAID. > > Notably - we've found that the 3Ware RAID controller does a better job than > the low end SCSI RAID at HW RAID support, and also exports JBOD at high > speeds. If you export JBOD on the low end SCSI RAID adapters, the > performance is also very poor, though generally faster than using HW RAID. Are there any recommendations for Qlogic controllers on Linux, scsi or fiber channel? I might be able to my hands on some. I have pci-x slots for AMD, Itanium, or POWER5 if the architecture makes a difference. Mark
>> >>>[root@pq-slave root]# /sbin/hdparm -tT /dev/sda >>> >>>/dev/sda: >>> Timing buffer-cache reads: 1816 MB in 2.00 seconds = 908.00 MB/sec >>> Timing buffered disk reads: 26 MB in 3.11 seconds = 8.36 MB/sec >>>[root@pq-slave root]# >> >>Can you post the "time dd if=/dev/zero of=bigfile bs=8k count=500000" >>results? Also do the reverse (read the file) with "time dd if=bigfile >>of=/dev/null bs=8k". I didn't see this come across before... here ya go: time dd if=/dev/zero of=bigfile bs=8k count=500000 500000+0 records in 500000+0 records out real 1m52.738s user 0m0.310s sys 0m36.590s time dd if=bigfile of=/dev/null bs=8k time dd if=bigfile of=/dev/null bs=8k 500000+0 records in 500000+0 records out real 4m38.742s user 0m0.320s sys 0m27.870s FYI on your hardware raid comment... I easily get 50 megs a second on my 3ware controllers and faster on my LSI SATA controllers. Sincerely, Joshua D. Drake > -- Your PostgreSQL solutions provider, Command Prompt, Inc. 24x7 support - 1.800.492.2240, programming, and consulting Home of PostgreSQL Replicator, plPHP, plPerlNG and pgPHPToolkit http://www.commandprompt.com / http://www.postgresql.org
>>> Can you post the "time dd if=/dev/zero of=bigfile bs=8k count=500000" >>> results? Also do the reverse (read the file) with "time dd if=bigfile >>> of=/dev/null bs=8k". > > I didn't see this come across before... here ya go: > > time dd if=/dev/zero of=bigfile bs=8k count=500000 > > 500000+0 records in > 500000+0 records out > > real 1m52.738s > user 0m0.310s > sys 0m36.590s So, that's 35MB/s, or 1/2 of a single disk drive. > time dd if=bigfile of=/dev/null bs=8k > > time dd if=bigfile of=/dev/null bs=8k > 500000+0 records in > 500000+0 records out > > real 4m38.742s > user 0m0.320s > sys 0m27.870s And that's 14MB/s, or < 1/4 of a single disk drive. > FYI on your hardware raid comment... I easily get 50 megs a second on my > 3ware controllers and faster on my LSI SATA controllers. Then you are almost getting one disk worth of bandwidth. By comparison, we get this using Linux software RAID on Xeon or Opteron: $ time dd if=/dev/zero of=bigfile bs=8k count=500000 500000+0 records in 500000+0 records out real 0m26.927s user 0m0.074s sys 0m8.769s $ time dd if=bigfile of=/dev/null bs=8k 500000+0 records in 500000+0 records out real 0m28.190s user 0m0.039s sys 0m8.349s with less CPU usage than HW SCSI RAID controllers. - Luke
Mark, On 7/28/05 4:43 PM, "Mark Wong" <markw@osdl.org> wrote: > Are there any recommendations for Qlogic controllers on Linux, scsi or > fiber channel? I might be able to my hands on some. I have pci-x slots > for AMD, Itanium, or POWER5 if the architecture makes a difference. I don't have a recommendation for a particular one, it's been too long (1998) since I've used one with Linux. However, I'd like to see a comparison between Emulex and Qlogic and a winner chosen. We've had some apparent driver issues with a client running Emulex on Linux, even using many different versions of the kernel. - Luke
Luke Lonergan wrote: > Mark, > > On 7/28/05 4:43 PM, "Mark Wong" <markw@osdl.org> wrote: > > > Are there any recommendations for Qlogic controllers on Linux, scsi or > > fiber channel? I might be able to my hands on some. I have pci-x slots > > for AMD, Itanium, or POWER5 if the architecture makes a difference. > > I don't have a recommendation for a particular one, it's been too long > (1998) since I've used one with Linux. However, I'd like to see a > comparison between Emulex and Qlogic and a winner chosen. We've had some > apparent driver issues with a client running Emulex on Linux, even using > many different versions of the kernel. Where is the most recent version of the COPY patch? -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073
Bruce, On 7/29/05 5:37 AM, "Bruce Momjian" <pgman@candle.pha.pa.us> wrote: > Where is the most recent version of the COPY patch? My direct e-mails aren't getting to you, they are trapped in a spam filter on your end, so you didn't get my e-mail with the patch! I've attached it here, sorry to the list owner for the patch inclusion / off-topic. - Luke
Attachment
"Luke Lonergan" <llonergan@greenplum.com> writes:
> On 7/29/05 5:37 AM, "Bruce Momjian" <pgman@candle.pha.pa.us> wrote:
>> Where is the most recent version of the COPY patch?
> I've attached it here, sorry to the list owner for the patch inclusion /
> off-topic.
This patch appears to reverse out the most recent committed changes in
copy.c.
regards, tom lane