Re: disk recommendations
On Thu, Oct 4, 2012 at 8:01 PM, Paul Robert Marino wrote: > This is actually fairly common with megaraid arrays esspecialy the ones > oemed by dell because they tend to rush them to market before they have Megaraid has *consistently* been a source of serious problems, requiring firmware updates, performing very poorly with server class operating systems that do not have last week's, not yet tested, beta drivers, and corrupting data at unpredictable times. If ordering high reliability equipment, I vastly prefer to go with Adaptec server class hardware, which is somewhat mre expensive, or Rocketport, which has been rock soled everyt time I'm privileged to use it. > worked out all the bugs in order to try to get the lattest greatest features > included in the spec sheet to make them seem superior to their compitition. > Chances are you need to update the firmware on the raid controller. There is > a fairly good chance that that 3rd box has a bad firmware revision. Updating > the firmware to the latest version will probably fix your issue. I've also seen some ghods-awful 3rd party repackaged, no-name cards that are listed in the kernel as "Adaptec" and other vendors, but if you look carefully had burned off chip numbers and look like they were manufactured by monkeys. Poor trace quality, poor component mounting, extremely thin gold on the contacts, gigantic screw holes to make assembly easier but make the mounting plates drift in alignment, etc. You might take a look at the actual card and make sure it's not one of these "it fell off my uncle's truck" pieces of hardware.
Re: disk recommendations
Similar findings here, where the first batch of drives in our hadoop clusters were WD greens. smartctl shows huge Load_Cycle_Count numbers for those drives which have been in service for a while (and they do indeed keep us busy with RMAs). Eventually we found this utility which can disable the absurdly short head-park timer from within linux: http://idle3-tools.sourceforge.net/ which might help, but I wouldn't choose to buy these drives again for this purpose. Graham On Thu, Oct 04, 2012 at 11:07:03AM -0600, Doug Johnson wrote: > Greetings, > > I have built many RAID systems using desktop disks and they are > generally quite stable. One of the issues with WD drives are with their > Green drives. By default, they park the heads after ~8 seconds of > inactivity. This will cause them to drop out of the array. The disk > firmware can be configured to disable this feature. I have had very good > luck with Samsung and Seagate drives. I have never spent the money on > Enterprise level drives. > > BTW: The head parking feature is notoriously bad. If you calculate 1 > park every 8 seconds. At constant usage, the drive will die in about 3 > months. Perhaps this feature is fine for a desktop, but it is not for a > server or production environment. -- - Graham Allan - I.T. Manager - al...@physics.umn.edu - (612) 624-5040 School of Physics and Astronomy - University of Minnesota -
RE: disk recommendations
I found that especially bad via USB adapters for the WD Green disks. For a 6 disk array. For 2 Disk via eSATA, works OK so far, but I really would stay away from the "green" disks for RAID. -- James Pulver LEPP Computer Group Cornell University -Original Message- From: owner-scientific-linux-us...@listserv.fnal.gov [mailto:owner-scientific-linux-us...@listserv.fnal.gov] On Behalf Of Doug Johnson Sent: Thursday, October 04, 2012 1:07 PM To: Steven Timm Cc: Ken Teh; scientific-linux-users Subject: Re: disk recommendations Greetings, I have built many RAID systems using desktop disks and they are generally quite stable. One of the issues with WD drives are with their Green drives. By default, they park the heads after ~8 seconds of inactivity. This will cause them to drop out of the array. The disk firmware can be configured to disable this feature. I have had very good luck with Samsung and Seagate drives. I have never spent the money on Enterprise level drives. BTW: The head parking feature is notoriously bad. If you calculate 1 park every 8 seconds. At constant usage, the drive will die in about 3 months. Perhaps this feature is fine for a desktop, but it is not for a server or production environment. Good luck, doug > > My understanding is that the main difference between desktop drives > and enterprise raid array drives in this regard is that the drive firmware > is configured to retry errors a lot longer on the desktop drives. > It is also my experience, although it was a few years ago on older > model WD drives, that the main thing that would produce problems of > disk drives dropping out of the array (desktop or enterprise) > is unexpected vibration of one kind or another. Easy for harmonics > to build up between the fans and the drive heads. > We have several Megaraid 9260-i controllers (and their successors and > their predecessors) in production but we did spend the money for the > enterprise drives. > > Steve Timm > > > On Thu, 4 Oct 2012, Ken Teh wrote: > > > I've run into problems trying to use desktop disks in a RAID array with a > > MegaRAID 9260-8i. I built 2 previous systems with desktop disks and did > > not > > have any problems but I've been unable to get this 3rd system to function > > stably. Disks dropped from the array except the disks are fine which I > > proved by deleting the disk group and starting again. > > > > This behaviour is consistent with Western Digital's discussion about TLER > > (time-limited error recovery) and their admonition to use enterprise disks > > instead of desktop disks. > > > > I was wondering if there are ways of getting around this problem without > > having to buy another set of disks. Googling suggests some options to try > > but I thought I'd used the list as a sounding board first before embarking > > on > > options. > > > > Thanks! > > > > -- > Steven C. Timm, Ph.D (630) 840-8525 > t...@fnal.gov http://home.fnal.gov/~timm/ > Fermilab Computing Division, Scientific Computing Facilities, > Grid Facilities Department, FermiGrid Services Group, Group Leader. > Lead of FermiCloud project. > Doug Johnsonemail: drj...@pizero.colorado.edu B390, Duane Physics (303)-492-4506 Office Boulder, CO 80309 (303)-492-5119 FAX http://www.aaccchildren.org Being right is not a justification for being rude. In fact, there are no justifications for being rude.
Re: disk recommendations
Greetings, I have built many RAID systems using desktop disks and they are generally quite stable. One of the issues with WD drives are with their Green drives. By default, they park the heads after ~8 seconds of inactivity. This will cause them to drop out of the array. The disk firmware can be configured to disable this feature. I have had very good luck with Samsung and Seagate drives. I have never spent the money on Enterprise level drives. BTW: The head parking feature is notoriously bad. If you calculate 1 park every 8 seconds. At constant usage, the drive will die in about 3 months. Perhaps this feature is fine for a desktop, but it is not for a server or production environment. Good luck, doug > > My understanding is that the main difference between desktop drives > and enterprise raid array drives in this regard is that the drive firmware > is configured to retry errors a lot longer on the desktop drives. > It is also my experience, although it was a few years ago on older > model WD drives, that the main thing that would produce problems of > disk drives dropping out of the array (desktop or enterprise) > is unexpected vibration of one kind or another. Easy for harmonics > to build up between the fans and the drive heads. > We have several Megaraid 9260-i controllers (and their successors and > their predecessors) in production but we did spend the money for the > enterprise drives. > > Steve Timm > > > On Thu, 4 Oct 2012, Ken Teh wrote: > > > I've run into problems trying to use desktop disks in a RAID array with a > > MegaRAID 9260-8i. I built 2 previous systems with desktop disks and did > > not > > have any problems but I've been unable to get this 3rd system to function > > stably. Disks dropped from the array except the disks are fine which I > > proved by deleting the disk group and starting again. > > > > This behaviour is consistent with Western Digital's discussion about TLER > > (time-limited error recovery) and their admonition to use enterprise disks > > instead of desktop disks. > > > > I was wondering if there are ways of getting around this problem without > > having to buy another set of disks. Googling suggests some options to try > > but I thought I'd used the list as a sounding board first before embarking > > on > > options. > > > > Thanks! > > > > -- > Steven C. Timm, Ph.D (630) 840-8525 > t...@fnal.gov http://home.fnal.gov/~timm/ > Fermilab Computing Division, Scientific Computing Facilities, > Grid Facilities Department, FermiGrid Services Group, Group Leader. > Lead of FermiCloud project. > Doug Johnsonemail: drj...@pizero.colorado.edu B390, Duane Physics (303)-492-4506 Office Boulder, CO 80309 (303)-492-5119 FAX http://www.aaccchildren.org Being right is not a justification for being rude. In fact, there are no justifications for being rude.
Re: disk recommendations
My understanding is that the main difference between desktop drives and enterprise raid array drives in this regard is that the drive firmware is configured to retry errors a lot longer on the desktop drives. It is also my experience, although it was a few years ago on older model WD drives, that the main thing that would produce problems of disk drives dropping out of the array (desktop or enterprise) is unexpected vibration of one kind or another. Easy for harmonics to build up between the fans and the drive heads. We have several Megaraid 9260-i controllers (and their successors and their predecessors) in production but we did spend the money for the enterprise drives. Steve Timm On Thu, 4 Oct 2012, Ken Teh wrote: I've run into problems trying to use desktop disks in a RAID array with a MegaRAID 9260-8i. I built 2 previous systems with desktop disks and did not have any problems but I've been unable to get this 3rd system to function stably. Disks dropped from the array except the disks are fine which I proved by deleting the disk group and starting again. This behaviour is consistent with Western Digital's discussion about TLER (time-limited error recovery) and their admonition to use enterprise disks instead of desktop disks. I was wondering if there are ways of getting around this problem without having to buy another set of disks. Googling suggests some options to try but I thought I'd used the list as a sounding board first before embarking on options. Thanks! -- Steven C. Timm, Ph.D (630) 840-8525 t...@fnal.gov http://home.fnal.gov/~timm/ Fermilab Computing Division, Scientific Computing Facilities, Grid Facilities Department, FermiGrid Services Group, Group Leader. Lead of FermiCloud project.
