slow system

[A.G.M. Velthof]

Hello to all,

I have an old system running 10.20.
On this system there is a directory with lots of small files, and this directory is also exported as a nfs filesystem.
A program moves about 10 files to a lower directory every 3 minutes.
This move takes extremely long (about 1 minute).
What is more likely to cause this problem.
The amount of little files, or the nfs export?

Regards, Alfons

[Yaroslav_4]

HP-UX for nfs use TCP transport as default, try to use udp instead if these files are not critical to much, or if you have 100% gud network. For small files hughe amount of time taken for establishing connectivity, and error checking with usage of sliding window. A lot of overhead used by TCP

[Leif Halvarsson_2]

Hi,

Is the program that move files running on a remote system (where the filesystem is nfs-mounted). If not, I can't belive the export of the filesystem should have any impact. If yes, try to perform the same file moves local.

[A.G.M. Velthof]

These files are very important.
The move action takes place on the system that exports the filesystem.

[Yaroslav_4]

just create some folder copy these files ther and mount to other machine. try to use udp for test purpose only

[Raj D.]

Hi A.G.M ,

You can try checking the move , when it is not exported , and surely can find the cause of this behaviour. It seems it taking time locally, and NFS is not causing problem.

But its better to check with unexporting the filesystem , and moving manualy and noting down the time. Also check your io activity on that disk.

# iostat 5 5

Cheers,
Raj.

[Victor BERRIDGE]

Hi,
A few things:
Except these moves we dont know what the box does, nor its load, is it running read/write intensive applications? are there 500 concurrent users?...
Have you any zombies?
...
Now about your files, I would believe since you say there are many small files in this directory with a lot of modifications you may have a very fragmented file system. Do you have Online-JFS?
Then try to defragment the file system:
fsadm -F vxfs -D -d -E -e -s $DIR>>
It can be done online but I would suggest to do this task when the box is not heavily loaded... launch it with cron...

Does this help?

The only time I had very bad performance was when someone disconnected external disks and connected them back but crossed the 2 cables...
All the best
Victor

[Muthukumar_5]

May be performance problem or some other application make usage of system?

Check the information's as,

# dmesg -c 1>/dev/null; dmesg -c

Is there any thing.

# iostat 5 5

# vmstat 5,5

# sar -A 5,5

Post this information.

hth.

[A.G.M. Velthof]

I will check the suggestions but can only do it in the weekend. (Saturday).

I will post wat I found next monday.

[Ted Buis]

Dave Olker wrote a whole book on NFS performance. http://docs.hp.com/en/B1031-90043/ch07s03.html
and
http://h21007.www2.hp.com/dspp/tech/tech_TechDocumentDetailPage_IDX/1,1701,952,00.html will give you some info. The first thing is to determine what the performance is that you are seeing, and compare it to what is possible on your old system. For example if you have a K-class with a 100BaseT card in an HP-PB slot and are getting 5MB/second, that is about all that the hardware will do. You will see less with NFS. If you FTP some files, you will get a good indication of the best that your hardware can do. NFS will always have greater overhead and lower performance than FTP. HP-UX only did UDP with 10.20.