on 10-17-2007 12:44 PM
On our main server I have a really strange problem (SLES 9 SP3):
# df -h /usr/sap
Filesystem Size Used Avail Use% Mounted on
/dev/cciss/c0d0p6 21G 20G 331M 99% /usr/sap
If I step into this directory and use "du" to check the usage I get
# du -hsx /usr/sap
2.8G /usr/sap
With "x" I excluded the (mounted) directories.
Any idea what the problem can be? Stale NFS handle? Any hints are appreciated.
--
Markus
Hello Markus,
A common problem I've found with /usr/sap/SID filesystems (since using Java instances), is the block size of the partition (or lvol working with LVM). The "default" block size for a big FS it's OK to use with Oracle datafiles (or other big files), but with the j2ee server there is a huge number of small files, and the real total size is smaller than the "occupied" size in disk.
Can you check your block size with
<b>/sbin/dumpe2fs /dev/cciss/c0d0p6 | grep 'Block size'</b>
...and paste the results?
Best Regards,
JC Llanes.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
Hi Juan,
that filesystem is a "fixed" one - neither using LVM nor ext2, an xfs filesystem:
# mount | grep "/usr/sap "
/dev/cciss/c0d0p6 on /usr/sap type xfs (rw)
# find . -mount -type f | wc -l
47943
I think I'll put that filesystem on a SAN system and copy the content over, this seems to be really strange to me.
--
Markus
Marked question as "assumed answered".
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
Hi,
Seems your trace files and stat files increased.
Please using sm50 to reset trace files and using ST03 delete statfiles of the applcation.
With Regards,
Lolla
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
Hi Markus,
XFS has a standard block size of 4k. I assume that in average we lose 2k space per file because of the 4k boundaries (e.g. a file wirh 6k allocates 8k on disk, and so on..).
As you have ~47.000 files under /usr/sap, this would only explain a loss of around 100MB, but not of 17.2GB!
df and du handle sparse files in a different way. Where du excludes the free space in sparse files, does df include it. But normally, there aren't any sparse files under /usr/sap.
Maybe the -x option does not work correctly. Do you have any SLES10/Solaris/other Unix system at hand?
Thanks,
Hannes Kuehnemund
SAP LinuxLab
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
Hi Hannes,
thank you for your answer.
I unmounted the share on the application servers, unmounted it locally and remounted it. Now it´s showing "normal" values:
# df -h /usr/sap
Filesystem Size Used Avail Use% Mounted on
/dev/cciss/c0d0p6 21G 2.8G 18G 14% /usr/sap
So apparently it was really a stale NFS handle (somewhere).
Thanx for your time!
Greetings,
--
Markus
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.