RE: Software RAID 0+1 with mdadm.
RAID10 will work with an odd number of disks! If really is cool! But, since you need control of what is where, you don't want RAID10. You should create RAID1 arrays. Each of your RAID1 arrays should have 2 disks, each on a different controller/channel. Then create a single RAID0 array out of the RAID1 arrays. Guy -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Holger Kiehl Sent: Thursday, January 27, 2005 3:13 AM To: Neil Brown Cc: linux-raid Subject: Re: Software RAID 0+1 with mdadm. I have since upgraded to mdadm 1.8 and setup a RAID10. However I need something that is production worthy. Is a RAID10 something I could rely on as well? Also under a RAID10 how do you tell it which drives you want mirrored? raid10 is 2.6 only, but should be quite stable. You cannot tell it which drives to mirror because you shouldn't care. You just give it a bunch of identical drives and let it put the data where it wants. If you really want to care (and I cannot imagine why you would - all drives in a raid10 are likely to get similar load) then you have to build it by hand - a raid0 of multiple raid1s. But what about redundancy? The only reason why on some systems I choose raid 1+0 and not raid10, is that I want the raid 1 always on two different controllers or channels. So if there is some problem with the SCSI bus you will only loose one half of your array. I think with raid10 it can be that you loose your complete array, because a whole raid1 can sit on a single controller/channel. Is this assumption correct, or does raid10 have some magic to solve this? Thanks, Holger - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Software RAID 0+1 with mdadm.
On Thu, Jan 27, 2005 at 04:24:34PM +1100, Neil Brown wrote: On Wednesday January 26, [EMAIL PROTECTED] wrote: This bug that's fixed in 1.9.0, is in a bug when you create the array? ie do we need to use 1.9.0 to create the array. I'm looking to do the same but my bootdisk currently only has 1.7.soemthing on it. Do I need to make a custom bootcd with 1.9.0 on it? This issue that will be fixed in 1.9.0 has nothing to do with creating the array. It is only relevant for stacked arrays (e.g. a raid0 made out of 2 or more raid1 arrays), and only if you are using mdadm --assemble --scan (or similar) to assemble your arrays, and you specify the devices to scan in mdadm.conf as DEVICES partitions (i.e. don't list actual devices, just say to get them from the list of known partitions). actually the last statement is not true, a missing close(mdfd); causes mdadm --assemble --scan to fail the first round even if you do specify DEV /dev/mdX in mdadm.conf. L. -- Luca Berra -- [EMAIL PROTECTED] Communication Media Services S.r.l. /\ \ / ASCII RIBBON CAMPAIGN XAGAINST HTML MAIL / \ - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
RAID-10 with odd number of disks (was Re: Software RAID 0+1 with mdadm.)
On Thu, Jan 27, 2005 at 10:50:43AM -0500, Guy wrote: RAID10 will work with an odd number of disks! If really is cool! It will? How? Does it just make the last mirror pair have 3 disks or what? If so then wouldn't it be better just to not have that disk under md and use it for someting else? -- The optimum programming team size is 1. Has Jurassic Park taught us nothing? -- pfilandr pgpitjuAjleuB.pgp Description: PGP signature
RE: Software RAID 0+1 with mdadm.
By the way the patches did not fix my boot issue with the RAID 1+0. I am using SuSe 9.2 if this helps. I've had to add in a few extra lines into my boot.local to get it show up at boot. Brad Dameron SeaTab Software www.seatab.com On Wed, 2005-01-26 at 14:14, J. Ryan Earl wrote: This bug that's fixed in 1.9.0, is in a bug when you create the array? ie do we need to use 1.9.0 to create the array. I'm looking to do the same but my bootdisk currently only has 1.7.soemthing on it. Do I need to make a custom bootcd with 1.9.0 on it? Thanks, -ryan -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Luca Berra Sent: Wednesday, January 26, 2005 9:17 AM To: linux-raid@vger.kernel.org Subject: Re: Software RAID 0+1 with mdadm. On Tue, Jan 25, 2005 at 02:28:21PM -0800, Brad Dameron wrote: Everything seems ok after boot. But again no /dev/md0 in /proc/mdstat. But then if I do a mdadm --assemble --scan it will then load /dev/md0. there is a bug in mdadm, see my mail patches for mdadm 1.8.0 or wait for 1.9.0 L. -- Luca Berra -- [EMAIL PROTECTED] Communication Media Services S.r.l. /\ \ / ASCII RIBBON CAMPAIGN XAGAINST HTML MAIL / \ - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: RAID-10 with odd number of disks (was Re: Software RAID 0+1 with mdadm.)
It rotates the pairs! Assume 3 disks, A, B and C. Each stripe would be on these disks: A+B C+A B+C A+B C+A B+C ... Maybe not exactly as above, but if not, something similar. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Andy Smith Sent: Thursday, January 27, 2005 11:19 AM To: 'linux-raid' Subject: RAID-10 with odd number of disks (was Re: Software RAID 0+1 with mdadm.) On Thu, Jan 27, 2005 at 10:50:43AM -0500, Guy wrote: RAID10 will work with an odd number of disks! If really is cool! It will? How? Does it just make the last mirror pair have 3 disks or what? If so then wouldn't it be better just to not have that disk under md and use it for someting else? -- The optimum programming team size is 1. Has Jurassic Park taught us nothing? -- pfilandr - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: RAID-10 with odd number of disks (was Re: Software RAID 0+1 with mdadm.)
On Thu, Jan 27, 2005 at 12:16:31PM -0500, Guy wrote: It rotates the pairs! Assume 3 disks, A, B and C. Each stripe would be on these disks: A+B C+A B+C A+B C+A B+C ... Hmm, difficult to visualise and comprehend if there are any differences as opposed to normal RAID-10. Is this anything like how RAID-1E works on IBM ServeRAID? pgpsex2AkWTN6.pgp Description: PGP signature
Re: RAID-10 with odd number of disks (was Re: Software RAID 0+1 with mdadm.)
On Thu, Jan 27, 2005 at 05:27:00PM +, Andy Smith wrote: On Thu, Jan 27, 2005 at 12:16:31PM -0500, Guy wrote: It rotates the pairs! Assume 3 disks, A, B and C. Each stripe would be on these disks: A+B C+A B+C A+B C+A B+C ... Hmm, difficult to visualise and comprehend if there are any differences as opposed to normal RAID-10. Is this anything like how RAID-1E works on IBM ServeRAID? This seems relevant: http://www.adaptec.com/worldwide/product/markeditorial.html?sess=nolanguage=English+USprodkey=raid_10_alternativestype=White%20Papers pgpRr143v611i.pgp Description: PGP signature
RE: RAID-10 with odd number of disks (was Re: Software RAID 0+1 with mdadm.)
A normal RAID 10 requires an even number of disks. Neil gave a detailed description. Maybe 6 months ago. Do a search for RAID10 or raid10. I just looked at the link you gave. RAID-1E does look like the RAID10 that md supports. Until today, I had never seen RAID-1E. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Andy Smith Sent: Thursday, January 27, 2005 12:42 PM To: 'linux-raid' Subject: Re: RAID-10 with odd number of disks (was Re: Software RAID 0+1 with mdadm.) On Thu, Jan 27, 2005 at 05:27:00PM +, Andy Smith wrote: On Thu, Jan 27, 2005 at 12:16:31PM -0500, Guy wrote: It rotates the pairs! Assume 3 disks, A, B and C. Each stripe would be on these disks: A+B C+A B+C A+B C+A B+C ... Hmm, difficult to visualise and comprehend if there are any differences as opposed to normal RAID-10. Is this anything like how RAID-1E works on IBM ServeRAID? This seems relevant: http://www.adaptec.com/worldwide/product/markeditorial.html?sess=nolanguage =English+USprodkey=raid_10_alternativestype=White%20Papers - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: irq timeout: status=0xd0 { Busy }
Hi, Thanks for the quick response! Guy wrote: Why would you fsck the failed member of a RAID5? You said format, please elaborate! You should verify the disk is readable. Verify readable? That is why I formatted the failed member, and did the fsck. I couldn't think of a better way to do it. However.. It looks like your disk is bad. But a read test would be reasonable. Try this: dd if=/dev/had of=/dev/null bs=64k It should complete without errors. It will do a full read test. I expect it will fail. I didn't think of trying 'dd', that's a good point. However, a moot point right now, the drive died last night. *Sigh* Anyway, thanks for the help! -CK - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: RAID-10 with odd number of disks (was Re: Software RAID 0+1 with mdadm.)
In the past, I have found the quite often, too often, the disk errors happened in the 1st sectors of the disk (and I still have to reboot often). It does not look good when losing a whole disk, eh? b- On Thu, 27 Jan 2005 12:16:31 -0500, Guy [EMAIL PROTECTED] wrote: It rotates the pairs! Assume 3 disks, A, B and C. Each stripe would be on these disks: A+B C+A B+C A+B C+A B+C ... Maybe not exactly as above, but if not, something similar. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Andy Smith Sent: Thursday, January 27, 2005 11:19 AM To: 'linux-raid' Subject: RAID-10 with odd number of disks (was Re: Software RAID 0+1 with mdadm.) On Thu, Jan 27, 2005 at 10:50:43AM -0500, Guy wrote: RAID10 will work with an odd number of disks! If really is cool! It will? How? Does it just make the last mirror pair have 3 disks or what? If so then wouldn't it be better just to not have that disk under md and use it for someting else? -- Using Opera's revolutionary e-mail client: http://www.opera.com/m2/ - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
