I would like to set up CentOS on 4 SATA hard drives that I would like to configure in RAID10. I read somewhere that Raid10 support is in the latest kernel, but I can't seem to get anaconda to let me create it. I only see raid 0, 1, 5, and 6.
Even when I tried to set up raid5 or raid1, it would not let me put the /boot partition on it, and I though that this was now possible.
Is it possible for me to set up the configuration I'm looking for?
Russ
I would like to set up CentOS on 4 SATA hard drives that I would like to configure in RAID10. I read somewhere that Raid10 support is in the latest kernel, but I can't seem to get anaconda to let me create it. I only see raid 0, 1, 5, and 6.
Even when I tried to set up raid5 or raid1, it would not let me put the /boot partition on it, and I though that this was now possible.
Is it possible for me to set up the configuration I'm looking for?
Russ
Cannot speak to raid 10 but have been running 4.4 an 5.0 with raid 1 and /boot partition on md0 for some time. Have not seen the issue you refer to.
bj
CentOS 5.0, Linux 2.6.18-8.1.1.el5 x86_64 00:15:44 up 2:37, 1 user, load average: 0.06, 0.19, 0.22
B.J. McClure wrote:
I would like to set up CentOS on 4 SATA hard drives that I would like to configure in RAID10. I read somewhere that Raid10 support is in the latest kernel, but I can't seem to get anaconda to let me create it. I only see raid 0, 1, 5, and 6.
Even when I tried to set up raid5 or raid1, it would not let me put the /boot partition on it, and I though that this was now possible.
Is it possible for me to set up the configuration I'm looking for?
Russ
Cannot speak to raid 10 but have been running 4.4 an 5.0 with raid 1 and /boot partition on md0 for some time. Have not seen the issue you refer to.
bj
Well as far as Raid10, it's not even an option for the installer. If I do select raid1 for the entire array, I only get the space of 3 of the 4 drives, and the installer still complains that I cannot put boot on a raid system.
Is there a how-to somewhere on getting this to work?
Russ
Well as far as Raid10, it's not even an option for the installer. If I do select raid1 for the entire array, I only get the space of 3 of the 4 drives, and the installer still complains that I cannot put boot on a raid system. Is there a how-to somewhere on getting this to work?
Russ
Kernel support does not automatically mean that code has been added to anaconda to support it...there was a thread about this earlier in the month where somebody recommended trying to create this manually in the installer by striping each pair of disks and mirroring those stripes. An alternative approach suggested switching over to a console to create things manually, outside of the installer.
-- jeremy
Ruslan Sivak wrote:
B.J. McClure wrote:
I would like to set up CentOS on 4 SATA hard drives that I would like to configure in RAID10. I read somewhere that Raid10 support is in the latest kernel, but I can't seem to get anaconda to let me create it. I only see raid 0, 1, 5, and 6.
Even when I tried to set up raid5 or raid1, it would not let me put the /boot partition on it, and I though that this was now possible.
Is it possible for me to set up the configuration I'm looking for?
Russ
Cannot speak to raid 10 but have been running 4.4 an 5.0 with raid 1 and /boot partition on md0 for some time. Have not seen the issue you refer to.
bj
Well as far as Raid10, it's not even an option for the installer. If I do select raid1 for the entire array, I only get the space of 3 of the 4 drives, and the installer still complains that I cannot put boot on a raid system. Is there a how-to somewhere on getting this to work?
I don't know if the installer will let you do it, but you are supposed to be able to create RAID1 devices, then stripe across them by using those md devices in a RAID0. I'm not sure if there is any advantage to that over using LVM to combine the RAID1 devices though. Personally I prefer to use RAID1 and deal with the space on separate mounted partitions since it permits recovering the data from any single drive but if I had to have a larger chunk I'd probably put /boot on a RAID1 and the rest in mirrored partitions combined in LVM.
Les Mikesell wrote:
Ruslan Sivak wrote:
B.J. McClure wrote:
I would like to set up CentOS on 4 SATA hard drives that I would like to configure in RAID10. I read somewhere that Raid10 support is in the latest kernel, but I can't seem to get anaconda to let me create it. I only see raid 0, 1, 5, and 6.
Even when I tried to set up raid5 or raid1, it would not let me put the /boot partition on it, and I though that this was now possible.
Is it possible for me to set up the configuration I'm looking for?
Russ
Cannot speak to raid 10 but have been running 4.4 an 5.0 with raid 1 and /boot partition on md0 for some time. Have not seen the issue you refer to.
bj
Well as far as Raid10, it's not even an option for the installer. If I do select raid1 for the entire array, I only get the space of 3 of the 4 drives, and the installer still complains that I cannot put boot on a raid system. Is there a how-to somewhere on getting this to work?
I don't know if the installer will let you do it, but you are supposed to be able to create RAID1 devices, then stripe across them by using those md devices in a RAID0. I'm not sure if there is any advantage to that over using LVM to combine the RAID1 devices though. Personally I prefer to use RAID1 and deal with the space on separate mounted partitions since it permits recovering the data from any single drive but if I had to have a larger chunk I'd probably put /boot on a RAID1 and the rest in mirrored partitions combined in LVM.
I just did an install where i set up boot on raid1 (sda1,sdb1 with sdc1 and sdd1 as spares), swap on raid0 (sda2, sdb2, sdc2, sdd2) and then created 2 LVM partitions /dev/md2 (raid1 of sda3 and sdb3) and /dev/md3 (raid1 of sdc3 and sdd3). I then combine the 2 partitions in LVM and put root on it.
Everything installed fine, but got stuck at the grub prompt.
I am now trying to set up raid10 manually by using mdadm, but it gives me an error, and when looking at dmesg, it says "md: personality for level 10 is not loaded!".
Does this mean that the currently compiled in kernel doesn't support raid10?
Russ
Ruslan Sivak wrote:
Les Mikesell wrote:
Ruslan Sivak wrote:
B.J. McClure wrote:
I would like to set up CentOS on 4 SATA hard drives that I would like to configure in RAID10. I read somewhere that Raid10 support is in the latest kernel, but I can't seem to get anaconda to let me create it. I only see raid 0, 1, 5, and 6.
Even when I tried to set up raid5 or raid1, it would not let me put the /boot partition on it, and I though that this was now possible.
Is it possible for me to set up the configuration I'm looking for?
Russ
Cannot speak to raid 10 but have been running 4.4 an 5.0 with raid 1 and /boot partition on md0 for some time. Have not seen the issue you refer to.
bj
Well as far as Raid10, it's not even an option for the installer. If I do select raid1 for the entire array, I only get the space of 3 of the 4 drives, and the installer still complains that I cannot put boot on a raid system. Is there a how-to somewhere on getting this to work?
I don't know if the installer will let you do it, but you are supposed to be able to create RAID1 devices, then stripe across them by using those md devices in a RAID0. I'm not sure if there is any advantage to that over using LVM to combine the RAID1 devices though. Personally I prefer to use RAID1 and deal with the space on separate mounted partitions since it permits recovering the data from any single drive but if I had to have a larger chunk I'd probably put /boot on a RAID1 and the rest in mirrored partitions combined in LVM.
I just did an install where i set up boot on raid1 (sda1,sdb1 with sdc1 and sdd1 as spares), swap on raid0 (sda2, sdb2, sdc2, sdd2) and then created 2 LVM partitions /dev/md2 (raid1 of sda3 and sdb3) and /dev/md3 (raid1 of sdc3 and sdd3). I then combine the 2 partitions in LVM and put root on it. Everything installed fine, but got stuck at the grub prompt.
Did you try to boot the install CD in rescue mode at that point? Grub doesn't know much about raid and only works because you can treat the mirrors as a singled disk. You should have been able to reinstall grub on /dev/sda (and again on /dev/sdb) from the rescue boot to fix things.
I am now trying to set up raid10 manually by using mdadm, but it gives me an error, and when looking at dmesg, it says "md: personality for level 10 is not loaded!". Does this mean that the currently compiled in kernel doesn't support raid10?
Can you build your RAID1 sets first, then combine those md devices in a RAID0?
On Fri, Apr 27, 2007 at 04:56:40PM -0400, Ruslan Sivak wrote:
I am now trying to set up raid10 manually by using mdadm, but it gives me an error, and when looking at dmesg, it says "md: personality for level 10 is not loaded!".
As it happens, I have just assembled four disks into a raid-10 array. Assembly is trivial; however there was a non-obvious step required to make it start the raid-10 array at boot time.
My notes are here:
http://wiki.xdroop.com/space/Linux/Software+Raid+compound+devices
Incidentally, I'm trying to use this as the back end of a nfs file server; does anyone have any advice for improving performance (lots of small files, lots of reads and writes and deletes, some large files) other than "run bonnie++ and iozone, fiddle, and repeat"? (Dell PowerEdge 2800, 2x36 + 4x300, CentOS 4.4 x86_64)
David Mackintosh wrote:
On Fri, Apr 27, 2007 at 04:56:40PM -0400, Ruslan Sivak wrote:
I am now trying to set up raid10 manually by using mdadm, but it gives me an error, and when looking at dmesg, it says "md: personality for level 10 is not loaded!".
As it happens, I have just assembled four disks into a raid-10 array. Assembly is trivial; however there was a non-obvious step required to make it start the raid-10 array at boot time.
My notes are here:
http://wiki.xdroop.com/space/Linux/Software+Raid+compound+devices
Funny that...I did not need a mdadm.conf file before...
Incidentally, I'm trying to use this as the back end of a nfs file server; does anyone have any advice for improving performance (lots of small files, lots of reads and writes and deletes, some large files) other than "run bonnie++ and iozone, fiddle, and repeat"? (Dell PowerEdge 2800, 2x36 + 4x300, CentOS 4.4 x86_64)
Backend? You mean it is the NFS server right?
Use ext3. Increase the size of the journal as appropriate (depends on size of the filesystem and the amount of RAM you have), make sure htree support is turned on, increase the number of nfs daemons.
David Mackintosh wrote:
On Fri, Apr 27, 2007 at 04:56:40PM -0400, Ruslan Sivak wrote:
I am now trying to set up raid10 manually by using mdadm, but it gives me an error, and when looking at dmesg, it says "md: personality for level 10 is not loaded!".
As it happens, I have just assembled four disks into a raid-10 array. Assembly is trivial; however there was a non-obvious step required to make it start the raid-10 array at boot time.
My notes are here:
http://wiki.xdroop.com/space/Linux/Software+Raid+compound+devices
Thank you for the notes. I followed them, but I'm still not having any luck installing. I go to shell and create the arrays and create the config files, but when I switch back to anaconda, it doesn't detect /dev/md10, only /dev/md11 and /dev/md12. I can't create another raid device in anaconda. What am I doing wrong? I tried setting up LVM when i first installed this, but it failed to boot.
Russ
On Mon, Apr 30, 2007 at 11:30:44AM -0400, Ruslan Sivak wrote:
Thank you for the notes. I followed them, but I'm still not having any luck installing. I go to shell and create the arrays and create the config files, but when I switch back to anaconda, it doesn't detect /dev/md10, only /dev/md11 and /dev/md12. I can't create another raid device in anaconda. What am I doing wrong? I tried setting up LVM when i first installed this, but it failed to boot.
I don't believe you can boot from any device that includes RAID-0 in its components. This is because the kernel is what knows how to drive a RAID-0 device, whereas the Grub loader knows how to do is read linearly.
At a bare minimum, your /boot must be non-RAID0 and non-LVM.
David Mackintosh wrote:
On Mon, Apr 30, 2007 at 11:30:44AM -0400, Ruslan Sivak wrote:
Thank you for the notes. I followed them, but I'm still not having any luck installing. I go to shell and create the arrays and create the config files, but when I switch back to anaconda, it doesn't detect /dev/md10, only /dev/md11 and /dev/md12. I can't create another raid device in anaconda. What am I doing wrong? I tried setting up LVM when i first installed this, but it failed to boot.
I don't believe you can boot from any device that includes RAID-0 in its components. This is because the kernel is what knows how to drive a RAID-0 device, whereas the Grub loader knows how to do is read linearly.
At a bare minimum, your /boot must be non-RAID0 and non-LVM.
I guess i forgot to mention a few things:
My boot is on /dev/md0 which is a raid1 array of 2 devices (/dev/sda1 and dev/sdb1) with 2 hotspares (/dev/sdc1 and /dev/sdd1). My swap partition is on /dev/md1 which is raid0 array of 4 devices (/dev/sd{a,b,c,d}2)
I want my / to be on /dev/md10 which is a raid0 array of 2 devices (/dev/md11 and /dev/md12) /dev/md11 is a raid1 array of 2 devices (/dev/sda3 and /dev/sdb3) /dev/md12 is a raid1 array of 2 devices (/dev/sdc3 and /dev/sdd3)
Previously I had created an LVM over /dev/md11 and /dev/md12, but after installation the system would not boot. Now I'm trying to create /dev/md10, which works fine in the shell, but I can't get it to show up in anaconda, so that I can start installing on it.
Russ
David Mackintosh wrote:
On Mon, Apr 30, 2007 at 11:30:44AM -0400, Ruslan Sivak wrote:
Thank you for the notes. I followed them, but I'm still not having any luck installing. I go to shell and create the arrays and create the config files, but when I switch back to anaconda, it doesn't detect /dev/md10, only /dev/md11 and /dev/md12. I can't create another raid device in anaconda. What am I doing wrong? I tried setting up LVM when i first installed this, but it failed to boot.
I don't believe you can boot from any device that includes RAID-0 in its components. This is because the kernel is what knows how to drive a RAID-0 device, whereas the Grub loader knows how to do is read linearly.
At a bare minimum, your /boot must be non-RAID0 and non-LVM.
Since there doesn't seem to be a good way to do this manually, would it be possible to create an install cd that has the updated anaconda and md packages that support raid10?
Russ
-
B.J. McClure -
David Mackintosh -
Feizhou -
Jeremy Rosengren -
Les Mikesell -
Ruslan Sivak