topic Re: Raw volume backup in Operating System - HP-UX

Raw volume backup

RBI — Sat, 04 Dec 2004 04:25:15 GMT

Can anybody tell me how can i take raw volume backup.
OS HPUX 11.11

Re: Raw volume backup

Florian Heigl (new acc) — Sat, 04 Dec 2004 04:37:48 GMT

Maybe give us some more info next time ;)

1. get the volume devicefile, something like /dev/vg08/rlvol38 or /dev/rdsk/cxtydz for a volume out of LVM control.
2. get tape tape devicefile
ioscan -fnkCtape (one of those 'best' thinggies)
3. Assure it's consistent, i.e. put oracle to DBA mode
4. I'd go with

dd if=/dev/vg0n/rlvol0n bs=1024k | gzip > /dev/rmt/0mn

(unless Your tape device uses h/w compression.)

Re: Raw volume backup

Stf — Sat, 04 Dec 2004 04:39:46 GMT

Hello,

I don't know exactly what you mean by raw volume backup, but if this is for backuping entire disk block by block you can use "dd" :
i.e.
dd if=/dev/dsk/cXtYdZ of=/dev/rmt/Wm bs=1024

where /dev/dsk/cXtYdZ is your source (disk)
where /dev/rmt/Wm is your destination (tape)
& where bs is the block size (default 512MB)

PS:I heard that with OpenView you can make raw logical volume backup

Stf ;-)

Re: Raw volume backup

RBI — Sat, 04 Dec 2004 05:03:09 GMT

Hi Florian Heigl

Thanks Great solution

But we are having 136 raw logical volumes that we cannot backup like this can u give some other solution

Re: Raw volume backup

Florian Heigl (new acc) — Sat, 04 Dec 2004 05:42:11 GMT

If You have an EMC in behind, use short-term used BCV's; if I guessed correctly and it's all database volumes You might be much better off saving from the DBMS itself especially if not every volume is 100% used.

I think every enterprise backup solution should be able to do reasonably fast backups of the raw volume either.

It now really depends on the hardware at hand and the backup window You have.

Are we talking about a monthly disaster backup or a nightly? hourly?

We don't use raw lv's, so I can only advise a bit -

if there is no 'big' backup software but a big jukebox available, use bacula. best SAN-attach it, map it to the database server, do the backup, unmap it.

even a script simply using dd,gzip and mt will do fine, maybe even better in that case.

if Your backup device is too slow for this, either use separate low-cost diskarrays (e.g. multiple of those 3TB ide-fc, they come at ~$4000 each), this gains best througput for a low price, but You shouldn't trust these farther than You can throw them, so maybe mirror them in LVM.

In general I'd strongly advise against backup up the raw lv's as You can't quickly recover that single lost table from them.

Maybe give me and the others some numbers, I'm at work since 8am now and guessing makes the brain ake.

How much data is there to backup (are we talking 136*2GB (buy a bunch of IDE drives *g*) or 136*100GB
How much capacity do the lv's add up to
What app wrote the data (maybe someone knows a trick)
Do You have something like tivoli,networker or openback or or ... at hand
Do You have at least 75% of the capacity available somewhere (i.e. huge fileserver idling during the time)
What tapes are You using?
How much time do You have for the backup
How much app downtime is allowed
Will You have to do it again
How often

add ?'s at Your liking.

Flo

Re: Raw volume backup

Bill Hassell — Sun, 05 Dec 2004 21:12:30 GMT

With so much data and so many volumes, do not consider dd!! There is nothing in the dd backup that will identify what you backed up or when it was backed up. Even worse, you may be tempted to put multiple backups on the same tape to save money. After a while, you'll probably have a mess on your hands and no way to sort out what you actually have on tape.

But most important, dd is a store-and-pray method. That means that there is no method to verify that the backup was successful. The hardware checksums for the disk and tape are all you have, not enough for valuable data. And as mentioned, you must either shutdown thwe database for the entire duration of the backup (might be many hours), or at least put the database into backup mode.

Using raw disk volumes for a database will more than triple your work as a system adminstrator when compared to filesystem backups. Do yourself (and your company) a big favor: purchase a commercial-grade backup software package such as HP's Data Protector. Most commercial backup tools can integrate raw volume backups into the database, and these programs will create complete backup records both on the tape as well as on a filesystem.

Re: Raw volume backup

Nguyen Anh Tien — Sun, 05 Dec 2004 21:54:45 GMT

If you have 136 raw logical volumes. You should give an eye on how to recover from raw backup and reorganize(many logical volumes are difficult to manage)

Re: Raw volume backup

bhavin asokan — Sun, 05 Dec 2004 22:07:36 GMT

hi,

for raw volume backup the best solution is hp dataprotector.you can have both filesystem and raw backup with this software.you can use full size of tape with this.ie. after backup of one day if space is available you can add second days backup also.this software provides protection of data and easy recovery ,etc.
this is a licenced software from hp.
regds,