Hello all,
I'm trying to install CentOS 6.3 to an mdadm partitionable array and not having any luck.
The installer only allows me to create one file system per md device, or specify the md device as a LVM physical volume. I don't want to do either, I want to create one md device and create multiple partitions on top of the md device.
I thought that perhaps the installer was preventing me from doing this because it wasn't possible to boot off a partitionable mdadm array, but through googling I don't believe this is the case. (See links at the bottom of this email)
I've tried the graphical installer and the text-mode installer, and neither gives me the ability to install to a partitionable mdadm array.
Even more annoying is that if I manually create such an array, partition it and create file systems, the installer will stop the array when starting the partitioning utility, preventing me from installing to the partitions I created.
Is there an advanced mode in the installer that I can force it to install to a partitionable md device, or is that not an option? I'd like to avoid having multiple md devices on the same physical drives, and unfortunately the application I'm installing doesn't place nicely with LVM.
Thanks, Hal
http://www.kernel.org/doc/Documentation/md.txt http://www.miquels.cistron.nl/raid/ https://bugzilla.redhat.com/show_bug.cgi?id=447818
On 07/11/12 15:10, Hal Martin wrote:
Hello all,
I'm trying to install CentOS 6.3 to an mdadm partitionable array and not having any luck.
The installer only allows me to create one file system per md device, or specify the md device as a LVM physical volume. I don't want to do either, I want to create one md device and create multiple partitions on top of the md device.
I thought that perhaps the installer was preventing me from doing this because it wasn't possible to boot off a partitionable mdadm array, but through googling I don't believe this is the case. (See links at the bottom of this email)
I've tried the graphical installer and the text-mode installer, and neither gives me the ability to install to a partitionable mdadm array.
Even more annoying is that if I manually create such an array, partition it and create file systems, the installer will stop the array when starting the partitioning utility, preventing me from installing to the partitions I created.
Is there an advanced mode in the installer that I can force it to install to a partitionable md device, or is that not an option? I'd like to avoid having multiple md devices on the same physical drives, and unfortunately the application I'm installing doesn't place nicely with LVM.
Thanks, Hal
Hello Hal,
AFAIK installing on to partitionable md is a hack that is not supported; it's cool, but is not supported by upstream. And when it breaks I hear it can be quite unpleasant to fix. What are your requirements exactly? Maybe we can advise an alternative partitioning etc.
On Wed, Nov 7, 2012 at 8:45 PM, Nux! wrote:
AFAIK installing on to partitionable md is a hack that is not supported; it's cool, but is not supported by upstream. And when it breaks I hear it can be quite unpleasant to fix.
Then perhaps this link should be removed from the CentOS wiki: http://wiki.centos.org/HowTos/Install_On_Partitionable_RAID1
As long as it is there on the Wiki, people will try it and run into problems as I did.
Alternately, put in a caveat "No Official support from upstream - try at your own risk"
-- Arun Khan
On Wed, Nov 7, 2012 at 10:15 AM, Nux! nux@li.nux.ro wrote:
On 07/11/12 15:10, Hal Martin wrote:
Hello all,
I'm trying to install CentOS 6.3 to an mdadm partitionable array and not having any luck.
The installer only allows me to create one file system per md device, or specify the md device as a LVM physical volume. I don't want to do either, I want to create one md device and create multiple partitions on top of the md device.
I thought that perhaps the installer was preventing me from doing this because it wasn't possible to boot off a partitionable mdadm array, but through googling I don't believe this is the case. (See links at the bottom of this email)
I've tried the graphical installer and the text-mode installer, and neither gives me the ability to install to a partitionable mdadm array.
Even more annoying is that if I manually create such an array, partition it and create file systems, the installer will stop the array when starting the partitioning utility, preventing me from installing to the partitions I created.
Is there an advanced mode in the installer that I can force it to install to a partitionable md device, or is that not an option? I'd like to avoid having multiple md devices on the same physical drives, and unfortunately the application I'm installing doesn't place nicely with LVM.
Thanks, Hal
Hello Hal,
AFAIK installing on to partitionable md is a hack that is not supported; it's cool, but is not supported by upstream. And when it breaks I hear it can be quite unpleasant to fix. What are your requirements exactly? Maybe we can advise an alternative partitioning etc.
The software we're testing does not support being installed on LVM, so if we want vendor support we need to install it on a partition.
Hardware RAID is going to be used for deployment, but for lab testing we were hoping to use mdadm and avoid buying expensive RAID controllers.
Creating multiple RAID arrays looks like the only supported solution, although it's quite annoying when partitonable md support would make it much simpler.
Was it ever supported upstream? Or did it fall out of favour when LVM became a popular installation method?
-Hal
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
On 07/11/12 15:43, Hal Martin wrote:
The software we're testing does not support being installed on LVM, so if we want vendor support we need to install it on a partition.
Hardware RAID is going to be used for deployment, but for lab testing we were hoping to use mdadm and avoid buying expensive RAID controllers.
Creating multiple RAID arrays looks like the only supported solution, although it's quite annoying when partitonable md support would make it much simpler.
Was it ever supported upstream? Or did it fall out of favour when LVM became a popular installation method?
-Hal
Then the solution is simple, run the server with a traditional, supported software raid and install a virtual machine on top of it. ;-)
AFAIK partitionable md has never been supported, by any distribution, not only by RedHat.
On Wed, Nov 7, 2012 at 8:40 PM, Hal Martin hal.martin@gmail.com wrote:
Hello all,
I'm trying to install CentOS 6.3 to an mdadm partitionable array and not having any luck.
The installer only allows me to create one file system per md device, or specify the md device as a LVM physical volume. I don't want to do either, I want to create one md device and create multiple partitions on top of the md device.
I thought that perhaps the installer was preventing me from doing this because it wasn't possible to boot off a partitionable mdadm array, but through googling I don't believe this is the case. (See links at the bottom of this email)
http://www.kernel.org/doc/Documentation/md.txt http://www.miquels.cistron.nl/raid/ https://bugzilla.redhat.com/show_bug.cgi?id=447818
Please see this thread from June/2012 on the subject matter
http://lists.centos.org/pipermail/centos/2012-June/126927.html
and the solution I found later on and posted in Oct/2012 -- http://lists.centos.org/pipermail/centos/2012-October/129654.html
I did install the latest dracut rpms per the bug reports listed in above but the fix is not 100% - for example if the second disk fails, I still get kernel panic
The first hit with search string "centos partitionable raid" gives me this http://wiki.centos.org/HowTos/Install_On_Partitionable_RAID1 which is already discussed in my June post.
It does install if you follow the steps listed for release 6.
In retrospect, I would suggest stay away from this method. Go the traditional route; carve up the two disks per your requirements and make the md devices for root, boot, home etc.
HTH, -- Arun Khan
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Arun Khan -
Hal Martin -
Nux!