OK, I have managed to get software RAID 1 running on my wonderful Proliant server but now have two challenges:
1) Fresh after an OS install and reboot, the RAID array starts to do its stuff but straight away (as part of the boot messages) I am told that the second disk is 'not ready for command' and the system hangs as soon as resyncing starts. I think this is fixed by adding an hdparm line to turn on DMA (I was also losing ticks), but cannot check this because...
2) As part of the testing, I rebooted the system with the second drive pulled out, the whole lot then boots and I can use mdadm -a to add the second drive to the mirrored pair. The drives resync at a decent speed and the pair works fine for the duration, but when I reboot the second drive is not part of the mirrored pair unless I manually add it again.
Looking at the md superblock for the second disk, I am wondering if all the attempts at setting up the RAID array have confused it as this is what I get - the last section looks wrong (??)
mdadm -E /dev/hde /dev/hde: Magic : a92b4efc Version : 00.90.00 UUID : b0dcd24f:7044414a:1f0ba458:adabce9e Creation Time : Thu Sep 16 06:21:59 2004 Raid Level : raid1 Device Size : 193157440 (184.21 GiB 197.79 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 0
Update Time : Wed May 11 09:13:50 2005 State : clean Active Devices : 1 Working Devices : 2 Failed Devices : 1 Spare Devices : 1 Checksum : 2652883e - correct Events : 0.15217
Number Major Minor RaidDevice State this 2 33 0 2 spare /dev/hde 0 0 22 3 0 active sync /dev/hdc3 1 1 0 0 1 faulty removed 2 2 33 0 2 spare /dev/hde
Any suggestions on getting this pair talking properly?
Thanks
Nigel
I had similar problems when I tried to use whole discs e.g. /dev/hde. Solution was to use partiotion (one for whole disc) = /dev/hde1 with type 0xfd.
-----Original Message----- From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On Behalf Of Ivo Panacek Sent: 11 May 2005 10:04 To: CentOS mailing list Subject: Re: [CentOS] Software RAID on Centos 4 - new issue
I had similar problems when I tried to use whole discs e.g. /dev/hde. Solution was to use partiotion (one for whole disc) = /dev/hde1 with type 0xfd.
-----Original Message----- From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On Behalf Of Ivo Panacek Sent: 11 May 2005 10:04 To: CentOS mailing list Subject: Re: [CentOS] Software RAID on Centos 4 - new issue
I had similar problems when I tried to use whole discs e.g. /dev/hde. Solution was to use partiotion (one for whole disc) = /dev/hde1 with type 0xfd.
Nigel Kendrick wrote:
I have just stuck the disk drives onto a plug-in ITE8212 dual-IDE card and now the systems boots and starts re-syncing properly so I reckon there may be a problem with the MegaRAID drivers - is it worth me taking this further and if so through what online channel - I guess it would go back to that large North American Operating System vendor?
MegaRAID drivers (and hardware they drive) doesn't have very bright history. When it works, it works. When it doesn't work, you are simply out of luck. From what you wrote, seems you belong in "out of luck" category.
BTW, shouldn't MegaRAID cards be hardware RAID? If you configure RAID in card's BIOS, instead of using software RAID, does it than work correctly?
-----Original Message----- From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On Behalf Of Aleksandar Milivojevic Sent: 11 May 2005 15:11 To: CentOS mailing list Subject: Re: [CentOS] Software RAID on Centos 4 - new issue
BTW, shouldn't MegaRAID cards be hardware RAID? If you configure RAID in card's BIOS, instead of using software RAID, does it than work correctly?
Nigel Kendrick wrote:
I tried setting up RAID 1 via the BIOS, but two drives were still presented to Linux. I tried 'ignoring' one of the drives and setting up Linux to use only one, but there were no signs of any hardware RAID sync taking place. Maybe this is a cut-down implementation as it's on the motherboard? It would be nice to get the MegaRAID interface going as the I/O performance from the ITE card is not as good. I had a look around the 'net via Google and couldn't find many useful docs on MegaRAID setup, but there do not seem to be many options to change in any case.
Just some ideas to "bypass" problematic MegaRAID drivers. Is there also "normal" IDE/ATA (or SATA) interface on the board? Is it possible to rewire things so that MegaRAID controller is not used (I guess whatever chipset motherboard uses, it has integrated IDE controller)? Is it possible to disable it in motherboard's BIOS?
If not, is plugging in an decent HW RAID card such as 3ware cards (or plain IDE/ATA or SATA controller, that can be bought dirt cheap) and an option?
Nigel Kendrick wrote:
- As part of the testing, I rebooted the system with the second drive
pulled out, the whole lot then boots and I can use mdadm -a to add the second drive to the mirrored pair. The drives resync at a decent speed and the pair works fine for the duration, but when I reboot the second drive is not part of the mirrored pair unless I manually add it again.
What's the partition type on the second drive? If you want kernel to start software RAID device on boot, all partitions that are component of such devices must be tagged as "linux raid autodetect" (type fd). You can use fdisk to easily check (use "p" command) and set (use "t" command) this.
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Aleksandar Milivojevic -
Ivo Panacek -
Nigel Kendrick