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Incorrect Free Space / xfs_growfs on RAID5 Volume ?

To: xfs@xxxxxxxxxxx
Subject: Incorrect Free Space / xfs_growfs on RAID5 Volume ?
From: Svavar Örn Eysteinsson <svavar@xxxxxxxx>
Date: Tue, 26 May 2009 09:51:20 +0000
Hi all.

I’m hoping that someone can help me out here, regarding growing a XFS filesystem
on a Adaptec RAID controller with RAID5 setup.

First of all, this is my setup :

Fedora Core 6.
Kernel : 2.6.27
(stock Fedora Core 6 xfsprogs)
Adaptec SATA Raid Controller 2820SA ( 8 port )

For 2 years now, I had running a RAID5 setup with 4x 500GB SATA disks
as one logical drive. That drive would have been /dev/sdb.
I made an xfs filesystem out of it and it gave me about 1.8 TB of usable data space.

No problems so far, nothing.

I recently added the 5th disks in the RAID5 setup, and reconfigured (Online Expansion)
with the Adaptec Storage Manager.
So the Adaptec SM tells me that I have 2.274 TB of space.
Parity space is : 465.626 GB and the Stripe size is 256K.

Well, the RAID controller setup is done. So I headed out to the fdisk section.

I deleted the /dev/sdb1 partition and made a new one right ahead.

(see below)

Partition number (1-4): 1
First cylinder (1-303916, default 1): 1
Last cylinder or +size or +sizeM or +sizeK (1-267349, default 267349): 267349

Disk /dev/sdb: 2499.7 GB, 2499794698240 bytes
255 heads, 63 sectors/track, 303916 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1      267349  2147480811   83  Linux

I issued a “w” command to write to the partition table and exited fdisk.

Mounted the /dev/sdb1 partition as /raid-data.

Did grow the XFS filesystem with xfs_growfs /raid-data

Now the strange part. When I issue “df -h” command it shows much smaller
disk space added then it should have.

(see below)

Filesystem            Size  Used Avail Use% Mounted on
/dev/sda3             269G  181G   75G  71% /
/dev/sda1             244M   20M  211M   9% /boot
tmpfs                1013M     0 1013M   0% /dev/shm
/dev/sdb1             2.0T  1.9T  191G  91% /raid-data

Using a “non -h” df command shows me :

Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda3            281636376 189165420  77933740  71% /
/dev/sda1               248895     20331    215714   9% /boot
tmpfs                  1036736         0   1036736   0% /dev/shm
/dev/sdb1            2147349736 1948095012 199254724  91% /raid-data

Any ideas? This is not acceptable as I inserted 500GB as additional space
to the RAID5 group and don’t have all of it. :(

So I checked the fragmentation with xfs_db and it told me
that the volume was having a 36.7% fragmentation.

I was going to issue a xfs_fsr but the system couldn’t find that command.

I removed the stock xfsprogs rpm version, downloaded the newest
xfsprogs source (xfsprogs-3.0.1). Build’it, installed it and issued
the xfs_fsr on the volume.

Nothing changed on the free space thing, It’s totally the same.

Filesystem            Size  Used Avail Use% Mounted on
/dev/sda3             269G  181G   75G  71% /
/dev/sda1             244M   20M  211M   9% /boot
tmpfs                1013M     0 1013M   0% /dev/shm
/dev/sdb1             2.0T  1.9T  191G  91% /raid-data

I then decided to use the xfs_growfs with the newest version(that is the version I
downloaded, configured and installed) on the volume.

Nothing happens, as the xfs_growfs says :

# xfs_growfs -d /raid-data
meta-data=/dev/sdb1 isize=256 agcount=36, agsize=15257482 blks
         =                       sectsz=512   attr=0
data = bsize=4096 blocks=536870202, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0
log      =internal               bsize=4096   blocks=32768, version=1
= sectsz=512 sunit=0 blks, lazy- count=0
realtime =none                   extsz=65536  blocks=0, rtextents=0
data size unchanged, skipping

So I really need some advice or help about this situation.
Did I do anything wrong ?

Is the metadata, and or log data on the xfs volume taking all the remain space
so I only get about 191GB free for data after the insert of 500GB disk ?

Thanks all.

Best regards,

Svavar - Reykjavik / Iceland

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