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How to get OS to see expanded partition size

campbellmc
Occasional Advisor

How to get OS to see expanded partition size

Hi,

I have migrated/expanded a RAID-1 (2 x 72GB) array on a proliant DL360 G5 (SmartArray p400i) to a RAID-10 (4 x 72GB) via hpacucli. The size appears to show correctly in /sys:

cat /sys/block/cciss\!c0d0/size
286611840

After I expanded the device, I ran 'partprobe /dev/cciss/c0d0', however fdisk still shows the device size to be 72GB.

I can't find anything in /sys or /proc which would allow me to tell the kernel of the new size, though an HP doc says the cciss driver should do this automatically

"The cciss driver communicated directly with the block layer to inform it of size changes
in the underlying logical disk devices."

(source: http://h20000.www2.hp.com/bc/docs/support/SupportManual/c02677069/c02677069.pdf )

Aside from a reboot, is there anyway I can get the kernel to see the new size of the underlying device?

Regards,

Campbell
9 REPLIES
Torsten.
Acclaimed Contributor

Re: How to get OS to see expanded partition size

You did not tell the OS, but it is probably a flavour of linux. Maybe a good idea to ask the linux sub-forum?

Hope this helps!
Regards
Torsten.

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Diego Castelli
Trusted Contributor

Re: How to get OS to see expanded partition size

did you issue fdisk or parted or any other partitioning utility, before partprobe?
Diego C.

MS MCSA Server 2003

HP Accredited Integration Specialist
campbellmc
Occasional Advisor

Re: How to get OS to see expanded partition size

Sorry, it is CentOS 5.5 x86_64. I did issue an fdisk before partprobe, yes.

Cheers,

Campbell
campbellmc
Occasional Advisor

Re: How to get OS to see expanded partition size

I will cross post this in the linux forum as well.

Regards,

Campbell
SMR
Valued Contributor

Re: How to get OS to see expanded partition size

The expansion/extension process does not modify your partitions, if that was your expected result, it will merely add more storage space to the block device (/dev/cciss/c0d0) your partition will continue to be of size 72GB but you now have the ability to create additional partitions on the newly added storage space.

If in the other hand, fdisk in unable to create additional partitions because it still thinks c0d0 is only 72GB and no more space is available then, like you said, a reboot might be a good approach to the problem.

Let us know how it goes,

Good luck!
campbellmc
Occasional Advisor

Re: How to get OS to see expanded partition size

Hi,

It wasn't the partition size I was worried about - I knew that had to be expanded. It was the fact that fdisk reported the *device size* to be 73GB. When I have done this with other disk controllers, the device size itself is changed, though I can't recall whether running 'partprobe' was a requirement. The strangeness (at least to me) in this situation was that /sys/block/cciss!c0d0/size was showing the new device size, but this was not picked up by fdisk.

I would like to know more about what was going on here, but that will have to wait until another time. For now, a reboot solved this issue for me.

Cheers,

Campbell
gregersenj
HPE Pro

Re: How to get OS to see expanded partition size

Did you extend the logical drive, on the smart array controller?

I can't help you with linux.

But reading the post, I wonder if have extended the logical drive.

When you add more drives to an array (Expand), all you do is you add the drives to the array.
This do not change the size og the logical drive. It may redistribute the data to the newly added disk also.

So now you've got a lot of nice unused space within the array.

You choise is:
Extend the excisting logical drive(s).
or
Create new logical drive(s).

You OS will not see any change, untill you have extended or createt new logical drive(s).

BR
/jag
campbellmc
Occasional Advisor

Re: How to get OS to see expanded partition size

Hi,

The logical drive was expanded (which is why the increased drive size was seen by the OS upon reboot). From hpacucli:

=> controller slot=0 logicaldrive 1 modify size=max

Warning: Extension may not be supported on certain operating systems.
Performing extension on these operating systems can cause data to
become inaccessible. See ACU documentation for details. Continue?
(y/n) y

=> controller slot=0 show config

Smart Array P400i in Slot 0 (Embedded) (sn: PH81MQ6085 )

array A (SAS, Unused Space: 0 MB)


logicaldrive 1 (136.7 GB, RAID 1+0, OK)

physicaldrive 1I:1:1 (port 1I:box 1:bay 1, SAS, 72 GB, OK)
physicaldrive 1I:1:2 (port 1I:box 1:bay 2, SAS, 72 GB, OK)
physicaldrive 1I:1:3 (port 1I:box 1:bay 3, SAS, 72 GB, OK)
physicaldrive 1I:1:4 (port 1I:box 1:bay 4, SAS, 72 GB, OK)

=>

Normally, this kind of expansion is not an issue under linux. I've only seen this issue with cciss driver.

Cheers,

Campbell
gregersenj
HPE Pro

Re: How to get OS to see expanded partition size

Ok.

Confusion, is that use the term expansion, for adding drives to an array.
And extension to make a logcal drive larger.

You have done so.

Can't help you with the os.

BR
/jag