Disk Fragmentation without JFS

[Tom_131]

I am attempting to defrag an hpux system. I do not have HP online JFS, so any attempt to use fsadm will fail for me. I even scaned the swlist -l products |grep -i JFS

This system has been online for nearly 4 years. It has 11.0 on it. It is really in need of a defrag.

If it would not take too much time, how would someone defrage a volume without using fsadm?

[James R. Ferguson]

Hi:

Assuming that you really need to defragment it, in the absence of Online JFS, you would need to backup the filesystem; 'newfs' it to create a new, empty filesystem; and reload it from backup.

I'm not at all sure that this would provide you any benefit at all -- at least one that you could measure.

Regards!

...JRF...

[steven Burgess_2]

Hi

You can with HFS but not vxfs.

http://aa11.cjb.net/hpux_admin/1997/0122.html

HTH

Steve

[steven Burgess_2]

Hi

I was going to suggest what James replied with but didn't think it would be worth it. Unless you have the downtime available


Is your system performance decreasing due to disk bottleneck ?

HTH

Steve

[S.K. Chan · Accepted solution]

It depends BUT rarely needed. This is because JFS by its nature is designed to minimize the need for defragmentation. I have done a couple and it really doesn't significantly improve io performance. Maybe in my case the FS was not that fragmented to begin with. First of all run this ..
# fsadm ???F vxfs ???E /
This gives a quick report on your "extent fragmentation". Replace "-E" with "-D"
to get report on "directory fragmnetation". Post the result here and we'll see if you need one. You do not need OnlineJFS to use fsadm to report fragmentation.

[Tom_131]

Thank all of you for the fast response.

The bottleneck is a feasible problem, but I am certian it is not the network access.

I imagined I would probobly need to pull the disks down.

If I have to, could you all tell me a safe procedure to do so an recreate the volume?

Thanks,

Tom

[Tom_131]

When I run the fsadm -F vsfs -E /tmp as a test I get:
vxfs fsadm: cannot open /tmp/lost+found/.fsadm - errno 2

any ideas?

thanks,

Tom

[steven Burgess_2]

Hi Thomas

Which logical volume are you thinking about ?
one in vg00 or elsewhere ? Is it just a data area or does it hold a database ? Depending on the area will depend on the method used to wipe the area and restore the data

HTH

Steve

[S.K. Chan]

It's "vxfs" not "vsfs" and "/tmp" MUST be a mount point.

[steven Burgess_2]

Hi

errno 2 is missing file or directory . S K does fsadm reference lost + found area ?

Steve

[S.K. Chan]

Yes it does Steven, it'll create a .fsadm file in the FS's lost+found everytime it's run. Thomas the lost+found dir should be 755 (root:root) typically. Is that what you got ?

[steven Burgess_2]

Thomas

You mention newtork access. Is there a delay when you are logging onto the server ?

This can be caused by hostname resolution. Are you resolving locally or to dns ?

Check your /etc/nsswitch.conf file

It is quickest to resolve to your hosts file initially

hosts : files [NOTFOUND=continue] dns

HTH

Steve

[Tom_131]

/tmp houses much of the temporary data along with certain areas of the opt file system that some old home-built programs used as a swap area.

/tmp is located on lvol4 vg00
/opt is located on lvol6 vg00


Does this help?

Thanks,
Tom

[Tom_131]

S.K. The .fsadm file is not created nor is a Lost+found either, but the permissions for the /tmp are 777 bin:bin.

Is this a permissions issue?

Thanks,

Tom

[Jeff Schussele]

Hi Thomas,

Are you the root user when running the fsadm command?

If so then you MUST have the lost+found dir on the mount point. If it's not there create it
mkdir /tmp/lost+found
should look like
drwxr-xr-x 2 root sys 96 Oct 11 15:45 lost+found

Set ownership & perms if necessary

Then just run
touch /tmp/lost+found/.fsadm

And it should look like
-rw------- 1 root sys 0 Oct 11 15:45 .fsadm

Then your fsadm command should run.

HTH,
Jeff

[Tom_131]

When I touch the directory /tmp/lost_found, I get an errno 20.

What's this error?

Thanks

[S.K. Chan]

It looks like lost+found does not exist in your mounted FS ? Do this then to recreate it ..
# cd /tmp
# mklost+found
Then re-run the fsadm again. Don't use the regular mkdir command.

[Jeff Schussele]

Hi Thomas,

Use mkdir to create the directory if it's not there

mkdir /tmp/lost+found

Then you can try the fsadm command. If it still fails then use touch to create the .fsadm file

touch /tmp/lost+found/.fsadm

Rgds,
Jeff

[steven Burgess_2]

Hi Thomas

for errno errors run this script and pass the number through it


#!/bin/sh

if [ $# -ne 1 ]
then
echo "Usage: $0 number" >&2
exit 1
fi
awk '/define/ { if ($3 == '"$1"' || $4 == '"$1"') print }' /usr/include/sys/errno.h

HTH

Steve

[Tom_131]

Ok- I got it to run, but how would you defrag the drive by taking the drive offline?

Thanks,
Tom

[Jeff Schussele]

Thanks S.K - learned something new today.
Wish I could go home now ;~)

Was totally unaware of that command.

Sorry Thomas - S.K. is entirely correct.

The lost+found is normally created by mkfs or newfs commands. Someone must have removed it at some point.

Rgds,
Jeff

[S.K. Chan]

You can't do it without OnlineJFS. Sorry ! the only way ... (like James had suggested) .. is to recreate your FS.

[steven Burgess_2]

Hi

Without jfs

for /tmp

backup the area

fbackup -v -f /dev/rmt/0m -i /tmp

shutdown -y 0

umount /tmp

newfs -F vxfs /dev/vg00/lvol?
mount /dev/vg00/lvol?

frecover -xvof /dev/rmt/0m /tmp

suggestions for /opt S K

ignite ?

I'm learning here

Steve

[steven Burgess_2]

oops

mount /dev/vg00/lvol6 /tmp

You probably know that

Steve

[James R. Ferguson]

Hi (again) Thomas:

You're wasting your time, in my option. '/tmp' should be disposable upon a reboot, so why defragment anything it it(?).

'/opt' should'nt be that volatile except for logs from things like Measureware.

If you want to unmount filesytems like '/opt', '/var' and '/tmp' you will find that the easiest way is to boot into single user mode rather than trying to kill processes holding files in them open.

Since you don't have Online JFS you can't defragment anything "online".

Regards!

...JRF...