Re: [PERFORM] Follow-Up: How to improve db performance with $7K?
Things might've changed somewhat over the past year, but this is from _the_ Linux guy at Dell... -tfo -- Thomas F. O'Connell Co-Founder, Information Architect Sitening, LLC Strategic Open Source — Open Your i™ http://www.sitening.com/ 110 30th Avenue North, Suite 6 Nashville, TN 37203-6320 615-260-0005 Date: Mon, 26 Apr 2004 14:15:02 -0500 From: Matt Domsch <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] Subject: PERC3/Di failure workaround hypothesis --uXxzq0nDebZQVNAZ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Apr 26, 2004 at 11:10:36AM -0500, Sellek, Greg wrote: > Short of ordering a Perc4 for every 2650 that I want to upgrade to RH > ES, is there anything else I can do to get around the Perc3/Di > problem? Our working hypothesis for a workaround is to do as follows: In afacli, set: Read Cache: enabled Write Cache: enabled when protected Then unplug the ROMB battery. A reboot is not necessary. The firmware will immediately drop into Write-Through Cache mode, which in our testing has not exhibited the problem. Setting the write cache to disabled in afacli doesn't seem to help - you've got to unplug the battery with it in the above settings. We are continuing to search for the root cause to the problem, and will update the list when we can. Thanks, Matt -- Matt Domsch Sr. Software Engineer, Lead Engineer Dell Linux Solutions linux.dell.com & www.dell.com/linux Linux on Dell mailing lists @ http://lists.us.dell.com On Apr 5, 2005, at 11:44 PM, Kevin Brown wrote: Thomas F.O'Connell wrote: I'd use two of your drives to create a mirrored partition where pg_xlog resides separate from the actual data. RAID 10 is probably appropriate for the remaining drives. Fortunately, you're not using Dell, so you don't have to worry about the Perc3/Di RAID controller, which is not so compatible with Linux... Hmm...I have to wonder how true this is these days. My company has a Dell 2500 with a Perc3/Di running Debian Linux, with the 2.6.10 kernel. The controller seems to work reasonably well, though I wouldn't doubt that it's slower than a different one might be. But so far we haven't had any reliability issues with it. Now, the performance is pretty bad considering the setup -- a RAID 5 with five 73.6 gig SCSI disks (10K RPM, I believe). Reads through the filesystem come through at about 65 megabytes/sec, writes about 35 megabytes/sec (at least, so says "bonnie -s 8192"). This is on a system with a single 3 GHz Xeon and 1 gigabyte of memory. I'd expect much better read performance from what is essentially a stripe of 4 fast SCSI disks. While compatibility hasn't really been an issue, at least as far as the basics go, I still agree with your general sentiment -- stay away from the Dells, at least if they have the Perc3/Di controller. You'll probably get much better performance out of something else. -- Kevin Brown [EMAIL PROTECTED] ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
Re: [PERFORM] Follow-Up: How to improve db performance with $7K?
On Wed, Apr 06, 2005 at 03:26:33PM +0200, PFC wrote: > Well, unless you have PCI 64 bits, the "standard" PCI does 133 MB/s > which is then split exactly in two times 66.5 MB/s for 1) reading from > the > PCI network card and 2) writing to the PCI harddisk controller. No wonder > you get this figure, you're able to saturate your PCI bus, but it does not > tell you a thing on the performance of your disk or network card... Note > that the server which serves the file is limited in the same way unless > the file is in cache (RAM) or it's PCI64. So... This is PCI-X. /* Steinar */ -- Homepage: http://www.sesse.net/ ---(end of broadcast)--- TIP 7: don't forget to increase your free space map settings
Re: [PERFORM] Follow-Up: How to improve db performance with $7K?
and we get about 65MB/sec sustained when writing to an ext3 filesystem (actually, when wgetting a file off the gigabit LAN :-) ). I haven't Well, unless you have PCI 64 bits, the "standard" PCI does 133 MB/s which is then split exactly in two times 66.5 MB/s for 1) reading from the PCI network card and 2) writing to the PCI harddisk controller. No wonder you get this figure, you're able to saturate your PCI bus, but it does not tell you a thing on the performance of your disk or network card... Note that the server which serves the file is limited in the same way unless the file is in cache (RAM) or it's PCI64. So... tested reading, though. /* Steinar */ ---(end of broadcast)--- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
Re: [PERFORM] Follow-Up: How to improve db performance with $7K?
On Tue, Apr 05, 2005 at 09:44:56PM -0700, Kevin Brown wrote: > Now, the performance is pretty bad considering the setup -- a RAID 5 > with five 73.6 gig SCSI disks (10K RPM, I believe). Reads through the > filesystem come through at about 65 megabytes/sec, writes about 35 > megabytes/sec (at least, so says "bonnie -s 8192"). This is on a > system with a single 3 GHz Xeon and 1 gigabyte of memory. I'd expect > much better read performance from what is essentially a stripe of 4 > fast SCSI disks. Data point here: We have a Linux software RAID quite close to the setup you describe, with an onboard Adaptec controller and four 146GB 1rpm disks, and we get about 65MB/sec sustained when writing to an ext3 filesystem (actually, when wgetting a file off the gigabit LAN :-) ). I haven't tested reading, though. /* Steinar */ -- Homepage: http://www.sesse.net/ ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
Re: [PERFORM] Follow-Up: How to improve db performance with $7K?
Thomas F.O'Connell wrote: > I'd use two of your drives to create a mirrored partition where pg_xlog > resides separate from the actual data. > > RAID 10 is probably appropriate for the remaining drives. > > Fortunately, you're not using Dell, so you don't have to worry about > the Perc3/Di RAID controller, which is not so compatible with > Linux... Hmm...I have to wonder how true this is these days. My company has a Dell 2500 with a Perc3/Di running Debian Linux, with the 2.6.10 kernel. The controller seems to work reasonably well, though I wouldn't doubt that it's slower than a different one might be. But so far we haven't had any reliability issues with it. Now, the performance is pretty bad considering the setup -- a RAID 5 with five 73.6 gig SCSI disks (10K RPM, I believe). Reads through the filesystem come through at about 65 megabytes/sec, writes about 35 megabytes/sec (at least, so says "bonnie -s 8192"). This is on a system with a single 3 GHz Xeon and 1 gigabyte of memory. I'd expect much better read performance from what is essentially a stripe of 4 fast SCSI disks. While compatibility hasn't really been an issue, at least as far as the basics go, I still agree with your general sentiment -- stay away from the Dells, at least if they have the Perc3/Di controller. You'll probably get much better performance out of something else. -- Kevin Brown [EMAIL PROTECTED] ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
Re: [PERFORM] Follow-Up: How to improve db performance with $7K?
Vivek Khera wrote: On Mar 31, 2005, at 9:01 PM, Steve Poe wrote: Now, we need to purchase a good U320 RAID card now. Any suggestions for those which run well under Linux? Not sure if it works with linux, but under FreeBSD 5, the LSI MegaRAID cards are well supported. You should be able to pick up a 320-2X with 128Mb battery backed cache for about $1k. Wicked fast... I'm suprized you didn't go for the 15k RPM drives for a small extra cost. Wow, okay, so I'm not sure where everyone's email went, but I got over a weeks worth of list emails at once. Several of you have sent me requests on where we purchased our systems at. Compsource was the vendor, www.c-source.com or www.compsource.com.The sales rep we have is Steve Taylor or you can talk to the sales manager Tom.I've bought hardware from them for the last 2 years and I've been very pleased. I'm sorry wasn't able to respond sooner. Steve, The LSI MegaRAID cards are where its at. I've had -great- luck with them over the years. There were a few weird problems with a series awhile back where the linux driver needed tweaked by the developers along with a new bios update. The 320 series is just as Vivek said, wicked fast. Very strong cards. Be sure though when you order it to specificy the battery backup either with it, or make sure you buy the right one for it. There are a couple of options with battery cache on the cards that can trip you up. Good luck on your systems! Now that I've got my email problems resolved I'm definitely more than help to give any information you all need. ---(end of broadcast)--- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
Re: [PERFORM] Follow-Up: How to improve db performance with $7K?
On Mar 31, 2005, at 9:01 PM, Steve Poe wrote: Now, we need to purchase a good U320 RAID card now. Any suggestions for those which run well under Linux? Not sure if it works with linux, but under FreeBSD 5, the LSI MegaRAID cards are well supported. You should be able to pick up a 320-2X with 128Mb battery backed cache for about $1k. Wicked fast... I'm suprized you didn't go for the 15k RPM drives for a small extra cost. ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Re: [PERFORM] Follow-Up: How to improve db performance with $7K?
I'd use two of your drives to create a mirrored partition where pg_xlog resides separate from the actual data. RAID 10 is probably appropriate for the remaining drives. Fortunately, you're not using Dell, so you don't have to worry about the Perc3/Di RAID controller, which is not so compatible with Linux... -tfo -- Thomas F. O'Connell Co-Founder, Information Architect Sitening, LLC http://www.sitening.com/ 110 30th Avenue North, Suite 6 Nashville, TN 37203-6320 615-260-0005 On Mar 31, 2005, at 9:01 PM, Steve Poe wrote: Thanks for everyone's feedback on to best improve our Postgresql database for the animal hospital. I re-read the PostgreSQL 8.0 Performance Checklist just to keep focused. We purchased (2) 4 x 146GB 10,000rpm SCSI U320 SCA drive arrays ($2600) and (1) Sun W2100z dual AMD64 workstation with 4GB RAM ($2500). We did not need a rack-mount server, so I though Sun's workstation would do fine. I'll double the RAM. Hopefully, this should out-perform our dual 2.8 Xeon with 4GB of RAM. Now, we need to purchase a good U320 RAID card now. Any suggestions for those which run well under Linux? These two drive arrays main purpose is for our database. For those messed with drive arrays before, how would you slice-up the drive array? Will database performance be effected how our RAID10 is configured? Any suggestions? Thanks. Steve Poe ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
[PERFORM] Follow-Up: How to improve db performance with $7K?
Thanks for everyone's feedback on to best improve our Postgresql database for the animal hospital. I re-read the PostgreSQL 8.0 Performance Checklist just to keep focused. We purchased (2) 4 x 146GB 10,000rpm SCSI U320 SCA drive arrays ($2600) and (1) Sun W2100z dual AMD64 workstation with 4GB RAM ($2500). We did not need a rack-mount server, so I though Sun's workstation would do fine. I'll double the RAM. Hopefully, this should out-perform our dual 2.8 Xeon with 4GB of RAM. Now, we need to purchase a good U320 RAID card now. Any suggestions for those which run well under Linux? These two drive arrays main purpose is for our database. For those messed with drive arrays before, how would you slice-up the drive array? Will database performance be effected how our RAID10 is configured? Any suggestions? Thanks. Steve Poe ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
