Re: raid6 check/repair

2007-12-07 Thread Gabor Gombas
On Wed, Dec 05, 2007 at 03:31:14PM -0500, Bill Davidsen wrote: BTW: if this can be done in a user program, mdadm, rather than by code in the kernel, that might well make everyone happy. Okay, realistically less unhappy. I start to like the idea. Of course you can't repair a running array

Re: Implementing low level timeouts within MD

2007-10-30 Thread Gabor Gombas
On Tue, Oct 30, 2007 at 12:08:07AM -0500, Alberto Alonso wrote: * Internal serverworks PATA controller on a netengine server. The server if off waiting to get picked up, so I can't get the important details. 1 PATA failure. I was surprised on this one, I did have good luck

Re: Raid-10 mount at startup always has problem

2007-10-29 Thread Gabor Gombas
On Mon, Oct 29, 2007 at 08:41:39AM +0100, Luca Berra wrote: consider a storage with 64 spt, an io size of 4k and partition starting at sector 63. first io request will require two ios from the storage (1 for sector 63, and one for sectors 64 to 70) the next 7 io

Re: Raid-10 mount at startup always has problem

2007-10-27 Thread Gabor Gombas
On Sat, Oct 27, 2007 at 09:50:55AM +0200, Luca Berra wrote: Because you didn't stripe align the partition, your bad. :) by default fdisk misalignes partition tables and aligning them is more complex than just doing without. Why use fdisk then? Use parted instead. It's not the kernel's fault

Re: Raid-10 mount at startup always has problem

2007-10-26 Thread Gabor Gombas
On Fri, Oct 26, 2007 at 11:15:13AM +0200, Luca Berra wrote: on a pc maybe, but that is 20 years old design. partition table design is limited because it is still based on C/H/S, which do not exist anymore. The MS-DOS format is not the only possible partition table layout. Other formats such

Re: Time to deprecate old RAID formats?

2007-10-26 Thread Gabor Gombas
On Fri, Oct 26, 2007 at 11:54:18AM +0200, Luca Berra wrote: but the fix is easy. remove the partition detection code from the kernel and start working on a smart userspace replacement for device detection. we already have vol_id from udev and blkid from ext3 which support detection of many

Re: Time to deprecate old RAID formats?

2007-10-26 Thread Gabor Gombas
On Fri, Oct 26, 2007 at 06:22:27PM +0200, Gabor Gombas wrote: You got the ordering wrong. You should get userspace support ready and accepted _first_, and then you can start the flamew^H^H^H^H^H^Hdiscussion to make the in-kernel partitioning code configurable. Oh wait that is possible even

Re: Time to deprecate old RAID formats?

2007-10-26 Thread Gabor Gombas
On Fri, Oct 26, 2007 at 02:41:56PM -0400, Doug Ledford wrote: * When using lilo to boot from a raid device, it automatically installs itself to the mbr, not to the partition. This can not be changed. Only 0.90 and 1.0 superblock types are supported because lilo doesn't understand the offset

Re: Time to deprecate old RAID formats?

2007-10-26 Thread Gabor Gombas
On Fri, Oct 26, 2007 at 02:52:59PM -0400, Doug Ledford wrote: In fact, no you can't. I know, because I've created a device that had both but wasn't a raid device. And it's matching partner still existed too. What you are talking about would have misrecognized this situation, guaranteed.

Re: Software RAID5 Horrible Write Speed On 3ware Controller!!

2007-07-18 Thread Gabor Gombas
On Wed, Jul 18, 2007 at 06:23:25AM -0400, Justin Piszcz wrote: I recently got a chance to test SW RAID5 using 750GB disks (10) in a RAID5 on a 3ware card, model no: 9550SXU-12 The bottom line is the controller is doing some weird caching with writes on SW RAID5 which makes it not worth

Re: Software RAID5 Horrible Write Speed On 3ware Controller!!

2007-07-18 Thread Gabor Gombas
On Wed, Jul 18, 2007 at 01:51:16PM +0100, Robin Hill wrote: Just to pick up on this one (as I'm about to reformat my array as XFS) - does this actually work with a hardware controller? Is there any assurance that the XFS stripes align with the hardware RAID stripes? Or could you just end up

Re: Fwd: Identify SATA Disks

2007-05-24 Thread Gabor Gombas
On Thu, May 24, 2007 at 09:29:04AM +1000, lewis shobbrook wrote: I've noted that device allocation can change with the generation of new initrd's and installation of new kernels; i.e. /dev/sdc becomes /dev/sda depending upon what order the modules load etc. I'm wondering if one could send a

Re: RAID1, hot-swap and boot integrity

2007-03-06 Thread Gabor Gombas
On Mon, Mar 05, 2007 at 06:32:32PM -0500, Mike Accetta wrote: Yes, we actually have a separate (smallish) boot partition at the front of the array. This does reduce the at-risk window substantially. I'll have to ponder whether it reduces it close enough to negligible to then ignore, but

Re: RAID1, hot-swap and boot integrity

2007-03-02 Thread Gabor Gombas
On Fri, Mar 02, 2007 at 09:04:40AM -0500, Mike Accetta wrote: Thoughts or other suggestions anyone? This is a case where a very small /boot partition is still a very good idea... 50-100MB is a good choice (some initramfs generators require quite a bit of space under /boot while generating the

Re: RAID1, hot-swap and boot integrity

2007-03-02 Thread Gabor Gombas
On Fri, Mar 02, 2007 at 10:40:32AM -0500, Justin Piszcz wrote: AFAIK mdadm/kernel raid can handle this, I had a number of occaisons when my UPS shut my machine down when I was rebuilding a RAID5 array, when the box came back up, the rebuild picked up where it left off. _If_ the resync got

Re: Odd (slow) RAID performance

2006-12-08 Thread Gabor Gombas
On Thu, Dec 07, 2006 at 10:51:25AM -0500, Bill Davidsen wrote: I also suspect that write are not being combined, since writing the 2GB test runs at one-drive speed writing 1MB blocks, but floppy speed writing 2k blocks. And no, I'm not running out of CPU to do the overhead, it jumps from

Re: Swap initialised as an md?

2006-11-12 Thread Gabor Gombas
On Fri, Nov 10, 2006 at 12:55:57PM +0100, Mogens Kjaer wrote: If one of your disks fails, and you have pages in the swapfile on the failing disk, your machine will crash when the pages are needed again. IMHO the machine will not crash just the application which the page belongs to will be

Re: Too much ECC?

2006-11-09 Thread Gabor Gombas
On Thu, Nov 09, 2006 at 03:30:55PM +0100, Dexter Filmore wrote: 195 Hardware_ECC_Recovered 3344107 For some models that's perfectly normal. Looking at a 5 year old 40GB Maxtor that's not been cooled too well I see 3 as the raw value. Different technology, different vendor, different

Re: New features?

2006-11-03 Thread Gabor Gombas
On Fri, Nov 03, 2006 at 02:39:31PM +1100, Neil Brown wrote: mdadm could probably be changed to be able to remove the device anyway. The only difficulty is: how do you tell it which device to remove, given that there is no name in /dev to use. Suggestions? Major:minor? If /sys/block still

Re: libata hotplug and md raid?

2006-10-17 Thread Gabor Gombas
On Tue, Oct 17, 2006 at 11:58:03AM +1000, Neil Brown wrote: udev can find out what needs to be done by looking at /sys/block/whatever/holders. Are you sure? $ cat /proc/mdstat [...] md0 : active raid1 sdd1[1] sdc1[0] sdb1[2] sda1[3] 393472 blocks [4/4] [] [...] $ ls -l

Re: libata hotplug and md raid?

2006-10-17 Thread Gabor Gombas
On Tue, Oct 17, 2006 at 10:07:07AM +0200, Gabor Gombas wrote: Vanilla 2.6.18 kernel. In fact, all the /sys/block/*/holders directories are empty here. Never mind, I just found the per-partition holders directories. Argh. Gabor

Re: avoiding the initial resync on --create

2006-10-10 Thread Gabor Gombas
On Mon, Oct 09, 2006 at 12:32:00PM -0400, Doug Ledford wrote: You don't really need to. After a clean install, the operating system has no business reading any block it didn't write to during the install unless you are just reading disk blocks for the fun of it. What happens if you have a

Re: avoiding the initial resync on --create

2006-10-10 Thread Gabor Gombas
On Tue, Oct 10, 2006 at 01:47:56PM -0400, Doug Ledford wrote: Not at all true. Every filesystem, no matter where it stores its metadata blocks, still writes to every single metadata block it allocates to initialize that metadata block. The same is true for directory blocks...they are

Re: remark and RFC

2006-08-18 Thread Gabor Gombas
On Thu, Aug 17, 2006 at 08:28:07AM +0200, Peter T. Breuer wrote: 1) if the network disk device has decided to shut down wholesale (temporarily) because of lack of contact over the net, then retries and writes are _bound_ to fail for a while, so there is no point in sending them now.

Re: second controller: what will my discs be called, and does it matter?

2006-07-07 Thread Gabor Gombas
On Thu, Jul 06, 2006 at 08:12:14PM +0200, Dexter Filmore wrote: How can I tell if the discs on the new controller will become sd[e-h] or if they'll be the new a-d and push the existing ones back? If they are the same type (or more precisely, if they use the same driver), then their order on

Re: IBM xSeries stop responding during RAID1 reconstruction

2006-06-20 Thread Gabor Gombas
On Tue, Jun 20, 2006 at 03:08:59PM +0200, Niccolo Rigacci wrote: Do you know if it is possible to switch the scheduler at runtime? echo cfq /sys/block/disk/queue/scheduler Gabor -- - MTA SZTAKI Computer and Automation

Re: IBM xSeries stop responding during RAID1 reconstruction

2006-06-20 Thread Gabor Gombas
On Tue, Jun 20, 2006 at 08:00:13AM -0700, Mr. James W. Laferriere wrote: At least one can do a ls of the /sys/block area then do an automated echo cfq down the tree . Does anyone know of a method to set a default scheduler ? RTFM:

Re: IBM xSeries stop responding during RAID1 reconstruction

2006-06-19 Thread Gabor Gombas
On Wed, Jun 14, 2006 at 10:46:09AM -0500, Bill Cizek wrote: I was able to work around this by lowering /proc/sys/dev/raid/speed_limit_max to a value below my disk thruput value (~ 50 MB/s) as follows: IMHO a much better fix is to use the cfq I/O scheduler during the rebuild. The default

Re: help wanted - 6-disk raid5 borked: _ _ U U U U

2006-04-20 Thread Gabor Gombas
On Mon, Apr 17, 2006 at 09:30:32AM +1000, Neil Brown wrote: It is arguable that for a read error on a degraded raid5, that may not be the best thing to do, but I'm not completely convinced. My opinion would be that in the degraded case md should behave as if it was a single physical drive, and

Re: replace disk in raid5 without linux noticing?

2006-04-20 Thread Gabor Gombas
On Wed, Apr 19, 2006 at 02:16:10PM -0400, Ming Zhang wrote: is this possible? * stop RAID5 * set a mirror between current disk X and a new added disk Y, and X as primary one (which means copy X to Y to full sync, and before this ends, only read from X); also this mirror will not have any