Operating System - HP-UX
1833758 Members
2510 Online
110063 Solutions
New Discussion

Cab be dump and swap on the same lvol? is it correct and not pottential problems?

 
MQ'ski
Regular Advisor

Cab be dump and swap on the same lvol? is it correct and not pottential problems?

see swapinfo
Kb Kb Kb PCT START/ Kb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 790528 0 790528 0% 0 - 1 /dev/vg00/lvol2
dev 4096 0 4096 0% 0 - 1 /dev/vg00/lvol9
reserve - 794620 -794620
memory 1683580 687516 996064 41%

see fstab file
dev/vg00/lvol3 / hfs defaults 0 1
/dev/vg00/lvol1 /stand hfs defaults 0 1
/dev/vg00/lvol4 /home hfs defaults 0 2
/dev/vg00/lvol5 /opt hfs defaults 0 2
/dev/vg00/lvol6 /tmp hfs defaults 0 2
/dev/vg00/lvol7 /usr hfs defaults 0 2
/dev/vg00/lvol8 /var hfs defaults 0 2
/dev/vg00/lvol9 / dump defaults 0 0
/dev/vg01/lvol1 /var/opt/HP-AIN/cores hfs defaults 0 2
/dev/vg01/lvol2 /var/opt/HP-AIN hfs defaults 0 2
/dev/vg01/lvol3 /var/opt/HP-AIN/cpeun/checkpoint hfs defaults 0 2
/dev/vg02/lvol1 /var/opt/HP-AIN/cpeun hfs defaults 0 2
/dev/vg00/lvol9 ... swap pri=1 0 0
7 REPLIES 7
Pete Randall
Outstanding Contributor

Re: Cab be dump and swap on the same lvol? is it correct and not pottential problems?

No, it shouldn't be a problem.

Pete

Pete
MQ'ski
Regular Advisor

Re: Cab be dump and swap on the same lvol? is it correct and not pottential problems?

Thanks...
I will aplicate it
Pete Randall
Outstanding Contributor

Re: Cab be dump and swap on the same lvol? is it correct and not pottential problems?

Marcin,

Actually, opinions vary on this subject. I think it's OK but see Bill McNamara's response in this thread:
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x48d8f715edc6d5118ff10090279cd0f9,00.html

Pete

Pete
Ceesjan van Hattum
Esteemed Contributor

Re: Cab be dump and swap on the same lvol? is it correct and not pottential problems?

Default swap and dump on lvol2. No problem!
Only on mirrored disks, the dump is cannot and will not be mirrored.
See 'lvlnboot -v'.

Regards,
Ceesjan

Bill Hassell
Honored Contributor

Re: Cab be dump and swap on the same lvol? is it correct and not pottential problems?

Swap and dump are mutually exclusive. If you are swapping then HP-UX is running. If your machine crashes then the swap area is meaningless and the OS writes the crash dump to this dual purpose area.

Now there is an advantage to having a separate dump area. If you have plenty of disk space, you can allocate about 25% of the size of your RAM to dedicated dump area(s). Then, if the machine crashes, when it comes back up, you can have the savecrash configuration set to LOG_ONLY=1 and SAVECRASH=0. This will speed up the reboot process significantly after a crash (saving a 24Gb crash dump takes a *LONG* time).

Since swap is on separate volumes, you can manualy run savecrash at a later time once things are back to normal. You can also run savecrash out to a tape rather than to /var/adm/crash. The tape image is a series of files in tar format.


Bill Hassell, sysadmin
MQ'ski
Regular Advisor

Re: Cab be dump and swap on the same lvol? is it correct and not pottential problems?

Ok. But I understand that it is possible to have mentioned my configuration
.....
/dev/vg00/lvol9 / dump defaults 0 0
....
dev/vg00/lvol9 ... swap pri=1 0 0

I have not too much choise.
I cannot tune kernel parameters because (I suppose it need reboot).
I can only choise free lvol.

As I understand. If system works it lvol9 will be used as swap area...
If sth happen swap area is not needen anymore and lvol9 will be used as dump.
Am I right.
So can I use this configuration?
MQ'ski
Regular Advisor

Re: Cab be dump and swap on the same lvol? is it correct and not pottential problems?

beside... after that I will have
swap on
/dev/vg00/lvol2 and /dev/vg00/lvol9
and
dump on /dev/vg00/lvol9