topic Re: specify the stripe LVM during cold installation in Operating System - HP-UX

specify the stripe LVM during cold installation

emily_3 — Wed, 07 May 2003 06:18:18 GMT

Is it possible to specify the stripe LVM during cold installation by using the configuration file. If could what's the format to specify the stripe LVM in the configuration file?

Re: specify the stripe LVM during cold installation

Frederic Sevestre — Wed, 07 May 2003 07:03:40 GMT

Hi,

Do you mean you want to strippe the lv on vg00 ?

Fr??d??ric

Re: specify the stripe LVM during cold installation

David_246 — Wed, 07 May 2003 07:08:58 GMT

Hi Emily,

There is no support for striping vg00.
Sorry, you'dd better not try it.

This I thought because of the direct load of /stand/vmunix outside of LVM.

Best Regs David

Re: specify the stripe LVM during cold installation

emily_3 — Wed, 07 May 2003 07:30:31 GMT

My server only have 2 harddisk, so is it possible to creat a stripe LVM.
My thinking is I have to specify lovl1, lovl2,lvol3 in vg00 in the root disk, and these couldn't be stripe LVM. So could I join the 2th. harddisk to vg00, and specify the other LVM to be stripe LVM? Can part of LVM is stripe, and part of LVM is not stripe under the same VG?

Re: specify the stripe LVM during cold installation

Frederic Sevestre — Wed, 07 May 2003 07:51:44 GMT

Hi,

You should not strippe the vg00.
The best thing to do is to use the second disk to mirror the vg00.

Create the vg00 on the first disk, then :

#pvcreate -B /dev/rdsk/cxtydz (your second disk)
#mkboot /dev/rdsk/cxtydz
#mkboot -a "hpux -lq" /dev/rdsk/cxtydz
#vgextend vg00 /dev/dsk/cxtydz

then for each lv of vg00 :
# lvextend -m 1 /dev/vg00/lvolx /dev/dsk/cxtydz

Regards,
Fr??d??ric

Re: specify the stripe LVM during cold installation

emily_3 — Wed, 07 May 2003 07:59:59 GMT

Actually this server is our Ignite (IUX) server, the purpose i want to creat some stripe LVM is to speed the s/w loading by seperating the s/w depot in different harddisk.
So is there any better way to do this?

Re: specify the stripe LVM during cold installation

Frederic Sevestre — Wed, 07 May 2003 08:18:49 GMT

I am not sure that stripping your lv will increase performance.

Regards,
Fr??d??ric

Re: specify the stripe LVM during cold installation

Karthik S S — Wed, 07 May 2003 08:20:40 GMT

Hi,

Striping is required only when,
a. You need better read and write performance
b. Data is not critical

Since you want to improve the performance of IUX server, I think mirror disk alone can do the trick. Because, IUX server is read intensive. Network clients boot from the IUX server and read the install image to install the OS and is not write intensive. Hence, You can plan for Mirroring the Disk. Mirrordisk UX comes built-in with HP-UX 11.11 Mission Critical OE.

Regards,
Karthik S S

Re: specify the stripe LVM during cold installation

Frederic Sevestre — Wed, 07 May 2003 08:23:35 GMT

You can create all vg00 logicals volumes on your first disk exept the depot's one. Then create the lv for the depot on the other disk :

Create vg00 and all lv on first disk.

# lvcreate lv_depot vg00
# lvextend -L /dev/vg00/lv_depot /dev/dsk/cxtydz (the second disk)
# newfs -F vxfs /dev/vg00/rlv_depot
Now the lv_depot is on the second disk.

Regards,
Fr??d??ric

Re: specify the stripe LVM during cold installation

emily_3 — Wed, 07 May 2003 08:40:24 GMT

hi techssk,

My understanding is since the IUX server is read intensive, so stripping should be able to have better performance. Why have to be both read and write intensive?
if my understanding is wrong, please correct me?

Re: specify the stripe LVM during cold installation

Karthik S S — Wed, 07 May 2003 09:18:23 GMT

Hi Emily,

Striping (RAID0) :
a. Better Read Performance ( Data is spread across multiple disks )
b. Better Write Performance ( Data can be written in multiple disks simultaneously )
c. Not fault-tolerant ( One disk fail and the whole volume fails )

Mirroring (RAID1) :
a. Best read performance ( Data can be read from the actual disk and from Mirrored disk as well )
b. Degraded write performance ( As it has to write the same data physically on to 2 disks (2 is minimum but you can have more) )
c. Fault tolerant ( One disk fails but you have the data on mirrored disk)

Now coming back to IUX Server. IUX Server is typically only read intensive. Hence the better option is to go for mirroring as it offers the best read performance and the meantime fault tolerance.

Hope this answers your question

Regards,
Karthik

Re: specify the stripe LVM during cold installation

Pete Randall — Wed, 07 May 2003 09:23:35 GMT

I do recall that there used to be an option during install to choose a striped layout for vg00, assuming you had more than one disk available. This was back in 10.20 on 700 series workstations. I don't know if such a thing is available for 11.x on servers or not.

Pete

Re: specify the stripe LVM during cold installation

Pete Randall — Wed, 07 May 2003 09:32:42 GMT

Further investigation indicates that this option is no longer available as of 11.0. The File System options you can select from are: "Whole Disk (not LVM); "Logical Volume Manager (LVM) with HFS"; and Logical Volume Manager (LVM) with VxFS.

Pete

Re: specify the stripe LVM during cold installation

Mark Landin — Wed, 07 May 2003 15:41:45 GMT

If you are talking about LVM striping, then you stripe a logical volume, not the entire volume group. You can easily set LVM striping up on a logical volume in the same area that you set HFS vs. JFS.

Note that even though you have enough disk space, sometimes you can't stripe a logical volume because the HP-UX installation utilities that configure the logical volumes will process them in alphabetical order based on their mount directory names. If you wanted to stripe /tmp, for instance, it will get built AFTER /, /opt, and /etc, and put them all on the primary (boot) physical volume. When it's time to build /tmp, though, you may not have enough free disk space on your primary disk to put half of /tmp on it.

In any case, LVM striping CAN be done, and while it may not be as performant or safe as Mirror Disk, it is vastly cheaper. :)

Re: specify the stripe LVM during cold installation

emily_3 — Thu, 08 May 2003 02:27:23 GMT

Thanks for your suggestions.
For my situation, mirror disk is impossible, because I couldn't put everything into one disk, while the other one is purly mirror. Because one disk don't have enough space to contain everything.

So maybe it's the time to upgrade the hardware to archive high performance.