Expand a raid volume

Expand a raid volume

[Dermot Paikkos]

Hi Admins,

I have a server with an Adaptec 2120S Raid controller. There are were 
6 x 174GB disks and one hot spare. I moved the hotspare into the RAID 
5 volume and the Adaptec Storage Manager shows the volume has grown 
from 681 to 821GB. 

My problem is that the OS doesn't see it that way. If I remount the 
volume it is still seen as a 681Gb volume.

/dev/sda5              681G   608G    38G  95% /data

It I do fdisk /dev/sda5 doesn't show me the same information, and 
doesn't list any size. The filesystem is ext3.

Disk /dev/sda5: 705.4 GB, 705416431104 bytes
255 heads, 63 sectors/track, 85761 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

     Device Boot      Start         End      Blocks   Id  System

When I tried to write the new disk label it failed

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 22: Invalid 
argument.
The kernel still uses the old table.

Does anyone know what I need to do to expand the current volume? Is 
it possible? 

TIA.
Dp.

Re: Expand a raid volume

[Tom Callahan]

Is partition 5 the last partition on that disk? If it is, you
theoretically can just delete partition 5, and then recreate it with a
bigger size. MAKE SURE TO TAKE A BACKUP FIRST....JUST IN CASE.

This is why LVM is your friend....If you had /dev/sda as a PV, and then
multiple VG's under that, with LV's under that....You could add the
disk, resize the PV, resize the VG and LV's and then resize the
filesystem, without making changes to the partition tables.

Thanks,
Tom Callahan



> On Tue, 2006-05-16 at 13:43 -0400, Dermot Paikkos wrote: 
> > Hi Admins,
> > 
> > I have a server with an Adaptec 2120S Raid controller. There are were 
> > 6 x 174GB disks and one hot spare. I moved the hotspare into the RAID 
> > 5 volume and the Adaptec Storage Manager shows the volume has grown 
> > from 681 to 821GB. 
> > 
> > My problem is that the OS doesn't see it that way. If I remount the 
> > volume it is still seen as a 681Gb volume.
> > 
> > /dev/sda5              681G   608G    38G  95% /data
> > 
> > It I do fdisk /dev/sda5 doesn't show me the same information, and 
> > doesn't list any size. The filesystem is ext3.
> > 
> > Disk /dev/sda5: 705.4 GB, 705416431104 bytes
> > 255 heads, 63 sectors/track, 85761 cylinders
> > Units = cylinders of 16065 * 512 = 8225280 bytes
> > 
> >      Device Boot      Start         End      Blocks   Id  System
> > 
> > When I tried to write the new disk label it failed
> > 
> > Calling ioctl() to re-read partition table.
> > 
> > WARNING: Re-reading the partition table failed with error 22: Invalid 
> > argument.
> > The kernel still uses the old table.
> > 
> > Does anyone know what I need to do to expand the current volume? Is 
> > it possible? 
> > 
> > TIA.
> > Dp.
> > 
> > -
> > To unsubscribe from this list: send the line "unsubscribe linux-admin"
> > in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: Expand a raid volume

[Dermot Paikkos]

So from what I've read so far, there is no way to do an on-line 
expansion of the filesystem, I have to destroy the current 
filesystem, create it a new and restore the data. Not what I had 
hoped for when I bought a RAID card that does on-line expansion!

> > It I do fdisk /dev/sda5 doesn't show me the same information, and
> > doesn't list any size. The filesystem is ext3.

As I don't seem to have a choice and I have to re-create the volume, 
would it be possible to use LVM on that that volume alone 
(/dev/sda5)?

I was under the impression that LVM was a software RAID system and I 
wanted to use hardware RAID, did I get that wrong too?

Here's my current filesystem:
/dev/sda2               26G    11G    14G  45% /
/dev/sda1              104M    17M    82M  17% /boot
/dev/shm               1.1G      0   1.1G   0% /dev/shm
/dev/sda6              107M      0   107M   0% /dos
/dev/sda5              681G   611G    35G  95% /data

OS: Fedora Core release 4 (Stentz)

The plan is to slowly increase the available size on this server so I 
want to swap the 174GB SCSI disks for 300GB ones. 

Should I recreate the whole system from scratch and use LVM?

Sorry I am looking for a few quick answers before reading all of 
http://www.tldp.org/HOWTO/LVM-HOWTO/index.html

TIA.
Dp.





On 16 May 2006 at 14:24, Tom Callahan wrote:

> Is partition 5 the last partition on that disk? If it is, you
> theoretically can just delete partition 5, and then recreate it with a
> bigger size. MAKE SURE TO TAKE A BACKUP FIRST....JUST IN CASE.
> 
> This is why LVM is your friend....If you had /dev/sda as a PV, and
> then multiple VG's under that, with LV's under that....You could add
> the disk, resize the PV, resize the VG and LV's and then resize the
> filesystem, without making changes to the partition tables.
> 
> Thanks,
> Tom Callahan
> 
> 
> 
> > On Tue, 2006-05-16 at 13:43 -0400, Dermot Paikkos wrote: 
> > > Hi Admins,
> > > 
> > > I have a server with an Adaptec 2120S Raid controller. There are
> > > were 6 x 174GB disks and one hot spare. I moved the hotspare into
> > > the RAID 5 volume and the Adaptec Storage Manager shows the volume
> > > has grown from 681 to 821GB. 
> > > 
> > > My problem is that the OS doesn't see it that way. If I remount
> > > the volume it is still seen as a 681Gb volume.
> > > 
> > > /dev/sda5              681G   608G    38G  95% /data
> > > 
> > > It I do fdisk /dev/sda5 doesn't show me the same information, and
> > > doesn't list any size. The filesystem is ext3.
> > > 
> > > Disk /dev/sda5: 705.4 GB, 705416431104 bytes
> > > 255 heads, 63 sectors/track, 85761 cylinders
> > > Units = cylinders of 16065 * 512 = 8225280 bytes
> > > 
> > >      Device Boot      Start         End      Blocks   Id  System
> > > 
> > > When I tried to write the new disk label it failed
> > > 
> > > Calling ioctl() to re-read partition table.
> > > 
> > > WARNING: Re-reading the partition table failed with error 22:
> > > Invalid argument. The kernel still uses the old table.
> > > 
> > > Does anyone know what I need to do to expand the current volume?
> > > Is it possible? 

Re: Expand a raid volume

[kalinix]

On Wed, 2006-05-17 at 12:31 +0100, Dermot Paikkos wrote:
> So from what I've read so far, there is no way to do an on-line 
> expansion of the filesystem, I have to destroy the current 
> filesystem, create it a new and restore the data. Not what I had 
> hoped for when I bought a RAID card that does on-line expansion!
> 
> > > It I do fdisk /dev/sda5 doesn't show me the same information, and
> > > doesn't list any size. The filesystem is ext3.
> 
> As I don't seem to have a choice and I have to re-create the volume, 
> would it be possible to use LVM on that that volume alone 
> (/dev/sda5)?
> 
> I was under the impression that LVM was a software RAID system and I 
> wanted to use hardware RAID, did I get that wrong too?
> 
> Here's my current filesystem:
> /dev/sda2               26G    11G    14G  45% /
> /dev/sda1              104M    17M    82M  17% /boot
> /dev/shm               1.1G      0   1.1G   0% /dev/shm
> /dev/sda6              107M      0   107M   0% /dos
> /dev/sda5              681G   611G    35G  95% /data
> 
> OS: Fedora Core release 4 (Stentz)
> 
> The plan is to slowly increase the available size on this server so I 
> want to swap the 174GB SCSI disks for 300GB ones. 
> 
> Should I recreate the whole system from scratch and use LVM?
> 
> Sorry I am looking for a few quick answers before reading all of 
> http://www.tldp.org/HOWTO/LVM-HOWTO/index.html
> 
> TIA.
> Dp.
> 
> 
> 
> 
> 
> On 16 May 2006 at 14:24, Tom Callahan wrote:
> 
> > Is partition 5 the last partition on that disk? If it is, you
> > theoretically can just delete partition 5, and then recreate it with a
> > bigger size. MAKE SURE TO TAKE A BACKUP FIRST....JUST IN CASE.
> > 
> > This is why LVM is your friend....If you had /dev/sda as a PV, and
> > then multiple VG's under that, with LV's under that....You could add
> > the disk, resize the PV, resize the VG and LV's and then resize the
> > filesystem, without making changes to the partition tables.
> > 
> > Thanks,
> > Tom Callahan
> > 
> > 
> > 
> > > On Tue, 2006-05-16 at 13:43 -0400, Dermot Paikkos wrote: 
> > > > Hi Admins,
> > > > 
> > > > I have a server with an Adaptec 2120S Raid controller. There are
> > > > were 6 x 174GB disks and one hot spare. I moved the hotspare into
> > > > the RAID 5 volume and the Adaptec Storage Manager shows the volume
> > > > has grown from 681 to 821GB. 
> > > > 
> > > > My problem is that the OS doesn't see it that way. If I remount
> > > > the volume it is still seen as a 681Gb volume.
> > > > 
> > > > /dev/sda5              681G   608G    38G  95% /data
> > > > 
> > > > It I do fdisk /dev/sda5 doesn't show me the same information, and
> > > > doesn't list any size. The filesystem is ext3.
> > > > 
> > > > Disk /dev/sda5: 705.4 GB, 705416431104 bytes
> > > > 255 heads, 63 sectors/track, 85761 cylinders
> > > > Units = cylinders of 16065 * 512 = 8225280 bytes
> > > > 
> > > >      Device Boot      Start         End      Blocks   Id  System
> > > > 
> > > > When I tried to write the new disk label it failed
> > > > 
> > > > Calling ioctl() to re-read partition table.
> > > > 
> > > > WARNING: Re-reading the partition table failed with error 22:
> > > > Invalid argument. The kernel still uses the old table.
> > > > 
> > > > Does anyone know what I need to do to expand the current volume?
> > > > Is it possible? 
> 
> -
> To unsubscribe from this list: send the line "unsubscribe linux-admin" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Maybe ext2online could help.



Calin

=================================================
Slous' Contention: If you do a job too well, you'll get stuck with it.

Re: Expand a raid volume

[urgrue]

 >> So from what I've read so far, there is no way to do an on-line
 >> expansion of the filesystem, I have to destroy the current
 >> filesystem, create it a new and restore the data. Not what I had
 >> hoped for when I bought a RAID card that does on-line expansion!

RAID creates a disk, on which you have partitions, on which you have 
filesystems. Until we get ZFS ported to linux (hopefully someday!), 
these are all different things entirely and have to be individually resized.
Download parted. It will resize your partitions and filesystems too. It 
has some limitations but it might be just what you need.

>> I was under the impression that LVM was a software RAID system and I 
>> wanted to use hardware RAID, did I get that wrong too?

LVM is not RAID. LVM has some RAIDish abilities (like mirroring) but 
LVM's main purpose is to allow flexible management of disks.
In other words, LVM allows you to make a "virtual" disk out of many 
physical disks.
Of course this sounds like RAID (adding disks to an array, etc) but 
essentially these are two different things designed for two different 
purposes, they just have some overlap. LVM shows up as a partition, 
which simplifies things. With RAID you will generally need to separately 
resize the array, the partition, and finally the filesystem.
Its generally a good idea to use LVM on servers, unless you know for 
sure your storage needs are going to remain quite static.

>> The plan is to slowly increase the available size on this server so I 
>> want to swap the 174GB SCSI disks for 300GB ones. 
>>
>> Should I recreate the whole system from scratch and use LVM?

Thats probably not necessary.
Your RAID card might allow you to replace the smaller disks and then 
expand them after the data has been rebuilt.
But overall switching to LVM is probably a good idea. I personally would 
  add the larger disks in a new array (you can do this one by one if you 
lack the space to add them all at once) and then create an LVM on top of 
that. Then you can migrate the data from the old array to the new one.