Thread: Good/Bad RAID and SCSI controllers?
Folks, I am hoping to start a thread where users post their experiences with various RAID and SCSI controllers running Postgres. When completed, I'll post it somewhere on Techdocs with a big disclaimer. I'll start it off: MYLEX AcceleRAID 170: Not supported under Linux 2.4 kernels. Performance under RAID 5 with 3 Maxtor UW SCSI disks good on read operations (slightly better than a single SCSI disk) but on large write operations poor, similar to low-end IDE disks in having disk-acccess bottlenecks. Suspected in our installation of locking up on very large simultaneous read/write operations, such as data tranformations on tables over 1 million records. (cause of lockup not firmly determined yet). (Josh Berkus 11/2002) -Josh Berkus
Josh Berkus wrote: > Folks, > > I am hoping to start a thread where users post their experiences with > various RAID and SCSI controllers running Postgres. When completed, > I'll post it somewhere on Techdocs with a big disclaimer. I'll start it > off: Sounds like a really good idea. There's already the beginnings of a page on Techdocs for this too. ;-) Here's two thoughts that might be helpful, although they're not RAID. Advansys UW SCSI controller: Brain damaged. Won't let standard Seagate Cheetah 10k RPM drives operating at all without having SCSI Disconnection turned off, and speed is forced to a maximum throughput of 6MB/s. 100% not recommended. Adaptec 29160 Ultra160 controller, BIOS version 3.10.0: Seems nice. Everything works well, most stuff is automatically configured, supported by just about everything. Haven't done throughput benchmarks though. Regards and best wishes, Justin Clift > MYLEX AcceleRAID 170: Not supported under Linux 2.4 kernels. > Performance under RAID 5 with 3 Maxtor UW SCSI disks good on read > operations (slightly better than a single SCSI disk) but on large write > operations poor, similar to low-end IDE disks in having disk-acccess > bottlenecks. Suspected in our installation of locking up on very large > simultaneous read/write operations, such as data tranformations on > tables over 1 million records. (cause of lockup not firmly determined > yet). (Josh Berkus 11/2002) > > -Josh Berkus -- "My grandfather once told me that there are two kinds of people: those who work and those who take the credit. He told me to try to be in the first group; there was less competition there." - Indira Gandhi
Justin, > Sounds like a really good idea. There's already the beginnings of a > page on Techdocs for this too. ;-) Where? I don't see it. -Josh
On Thu, 12 Dec 2002, Justin Clift wrote: > Josh Berkus wrote: > > Folks, > > > > I am hoping to start a thread where users post their experiences with > > various RAID and SCSI controllers running Postgres. When completed, > > I'll post it somewhere on Techdocs with a big disclaimer. I'll start it > > off: > > Sounds like a really good idea. There's already the beginnings of a page on Techdocs for this too. ;-) > > Here's two thoughts that might be helpful, although they're not RAID. > > Advansys UW SCSI controller: Brain damaged. Won't let standard Seagate Cheetah 10k RPM drives operating at all without > having SCSI Disconnection turned off, and speed is forced to a maximum throughput of 6MB/s. 100% not recommended. > > Adaptec 29160 Ultra160 controller, BIOS version 3.10.0: Seems nice. Everything works well, most stuff is automatically > configured, supported by just about everything. Haven't done throughput benchmarks though. I'll throw a vote in behind the SymBIOS / LSI logic cards. They are quite stable and reliable, and generally faster than most other cards. I've got an UW symbios card at home I'll have to truck into work to play with so I can compare it to my Adaptecs here. I picked it up on Ebay (the symbios card) for $30, and it had a network interface on it too, but the guy didn't know what kind it was. Turned out to be gig ethernet interface with the yellowfin chipset. not a bad deal, when you think about it. poor thing gets to run my scanner, a tape drive, and an old Plextor 12 Plex CDROM drive. I'd like to hook up something with the gigabit nic someday while it's still considered somewhat fast. :-) For insight into the SCSI cards that Linux supports and what the maintainers think, I highly recommend a tour of the driver source code files. It's amazing how often the words "brain damaged" and "piece of crap" show up there.
Josh Berkus wrote: > Justin, > > >>Sounds like a really good idea. There's already the beginnings of a >>page on Techdocs for this too. ;-) > > > Where? I don't see it. Was thinking about this: http://techdocs.postgresql.org/guides/DiskTuningGuide :-) Regards and best wishes, Justin Clift > -Josh > -- "My grandfather once told me that there are two kinds of people: those who work and those who take the credit. He told me to try to be in the first group; there was less competition there." - Indira Gandhi
On 11 Dec 2002 at 15:34, scott.marlowe wrote: > On Thu, 12 Dec 2002, Justin Clift wrote: > > Advansys UW SCSI controller: Brain damaged. Won't let standard Seagate Cheetah 10k RPM drives operating at all without > > having SCSI Disconnection turned off, and speed is forced to a maximum throughput of 6MB/s. 100% not recommended. > > > > Adaptec 29160 Ultra160 controller, BIOS version 3.10.0: Seems nice. Everything works well, most stuff is automatically > > configured, supported by just about everything. Haven't done throughput benchmarks though. > > I'll throw a vote in behind the SymBIOS / LSI logic cards. They are quite > stable and reliable, and generally faster than most other cards. I've got > an UW symbios card at home I'll have to truck into work to play with so I > can compare it to my Adaptecs here. > > I picked it up on Ebay (the symbios card) for $30, and it had a network > interface on it too, but the guy didn't know what kind it was. Turned out > to be gig ethernet interface with the yellowfin chipset. not a bad deal, > when you think about it. poor thing gets to run my scanner, a tape drive, > and an old Plextor 12 Plex CDROM drive. I'd like to hook up something > with the gigabit nic someday while it's still considered somewhat fast. > :-) Right now page on techdocs is pretty thin on such details. I suggest these authors to put this information(barring humour etc. Just experiences) on that document. Secondly I see my name there as contributor but I do not recall any contribution. Anyway since I would like to have my name there, I will put some info there as well. Bye Shridhar -- Rules for driving in New York: (1) Anything done while honking your horn is legal. (2) You may park anywhere if you turn your four-way flashers on. (3) A red light means the next six cars may go through the intersection.