Incorrect Free Space / xfs_growfs on RAID5 Volume ?

Svavar Örn Eysteinsson
2009-05-26T09:51:10Z

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.
Great.

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