how often the OS buffer cache is sync'd.

[Xavier BLANC]

Ok
I'm going to modify dbc_min_pct and max ( not today, this is prod environment).
And see what happen !

For JFS
swlist -l bundle|grep -i OnlineJFS produce nothing ( I've tried also with fileset ).
Can you tell me on what CD is the JFS, and if I go to JFS what I need to know. Should I backup and recreate my filesystem ( I currently use LVM ).

Disk config is Fiber channel bus -> DS2400 -> several 18Gb disk.
The db is on a Mirror-ux disk ( 1 - 1 ) .
No raid (hard)

As we have plenty disk I was wondering about stripping but I've no knowlegde on this. Do you think someone on this forum can guide me to do it in the future. Or does it require HP engineer !
I know quite well HPUX and understand HP LVM.

Thank again to all
Xavier

[Fred Ruffet]

OnlineJFS is not free. You will need to contact your resseller. OnlineJFS main goal is to provide Online resizing of FS (Do not need to unmount a FS to add space). Install needs a reboot.

If you have already set up mirroring and have space for it, I would tell you not to stripe.

You don't need someone to set up stripping. It is not harder than mirroring. There are just things you must do and some not. If you plan to do it, just ask advices here.

Regards,

Fred

[Victor BERRIDGE]

Hi Xavier,
You will have to buy Online-JFS...

I do lvm striping over a HDS SAN (raid5...)
to get something like loadbalancing... (I know there is a software for that but its again a question of time ($$$)...

I believe you will gain in I/O bandwidth (I do see quite a difference...)by striping - and its not difficult...
create striped swap...
#/sbin/lvcreate -l 1016 -n lvol2 -i 4 -I 256 -r y -C n -s y -p w -d p s4vg01

Here is how to see queue depth and I/O timeout:
# pvdisplay /dev/dsk/c4t0d0
--- Physical volumes ---
PV Name /dev/dsk/c4t0d0
PV Name /dev/dsk/c8t0d0 Alternate Link
VG Name /dev/s4vg01
PV Status available
Allocatable yes
VGDA 2
Cur LV 8
PE Size (Mbytes) 4
Total PE 3472
Free PE 1045
Allocated PE 2427
Stale PE 0
IO Timeout (Seconds) 180
Autoswitch On

# scsictl -a /dev/rdsk/c4t0d0
immediate_report = 0; queue_depth = 8

All the best
Victor

[Fred Ruffet]

If you plan to stripe, create VGs where all LVs are stripped on the same number of disks (Like for Mirroring). If you don't, you could came to a situation with a LV that you cannot extend on a VG with plenty of space.

For your DB, Stripping may not be a good thing unless you have a SAN array with multiple paths to disks (Controlers, Fibers and LUN created to balance accesses). In other cases (classic SCSI internal drives or SCSI array), you may have better IOs with Mirror.

Regards,

Fred