[linux-lvm] Using LVM to snapshot Oracle

[linux-lvm] Using LVM to snapshot Oracle

[Mitchell Christensen]

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Hey,

 

I was wondering about the feasibility of using the LVM snapshot facility
to backup/restore Oracle.  Does this make sense?

 

A few issues that I am concerned about are,

*	Would it be any better/faster/cheaper than RMAN (the standard
Oracle backup facility)?
*	Would hot-backups be possible, or would the database need to be
in a quiescent state?
*	Is anyone else out there doing this (or anything similar)?
*	Is it reasonable to expect that I could simply take a snapshot
of all Oracle related files and be able to restore a viable Oracle
instance from that snapshot?

Any feedback and/or advice would be greatly appreciated.

 

-Mitch


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Re: [linux-lvm] Using LVM to snapshot Oracle

[Luca Berra]

On Mon, Feb 20, 2006 at 11:28:56AM -0800, Mitchell Christensen wrote:
>I was wondering about the feasibility of using the LVM snapshot facility
>to backup/restore Oracle.  Does this make sense?
>
Yes
>
>A few issues that I am concerned about are,
>
>*	Would it be any better/faster/cheaper than RMAN (the standard
>Oracle backup facility)?
it will work in a different manner,
rman is more complex to handle. but it will give you some more features,
like integrated archive log management and point in time restores.

>*	Would hot-backups be possible, or would the database need to be
>in a quiescent state?
you can do hot backup, but you will need to tell oracle you are doing
so:

you will need to have oracle in archive log mode

you will need to manually set all tablespaces in backup mode:
alter tablespace XXX begin backup; (for all tablespaces)
alter system switch logfile;
do your backup including the archive logs
alter tablespace XXX end backup; (for all tablespaces)

it is a simple sql script to code

>*	Is anyone else out there doing this (or anything similar)?
sure

>*	Is it reasonable to expect that I could simply take a snapshot
>of all Oracle related files and be able to restore a viable Oracle
>instance from that snapshot?
after restore you will have to "recover database" to apply the archive
logs and make the database consistent.

L.


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Luca Berra -- bluca@comedia.it
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Re: [linux-lvm] Using LVM to snapshot Oracle

[Luca Berra]

On Mon, Feb 20, 2006 at 11:05:32PM +0100, Luca Berra wrote:
to clarify:
>you can do hot backup, but you will need to tell oracle you are doing
>so:
>
>you will need to have oracle in archive log mode
>
>you will need to manually set all tablespaces in backup mode:
>alter tablespace XXX begin backup; (for all tablespaces)
>alter system switch logfile;
the snapshot creation part goes here

NO >do your backup including the archive logs

>alter tablespace XXX end backup; (for all tablespaces)

do your backup here including the archive logs
destroy the snapshot here.

>it is a simple sql script to code
>

-- 
Luca Berra -- bluca@comedia.it
        Communication Media & Services S.r.l.
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Re: [linux-lvm] Using LVM to snapshot Oracle

[Klaus Strebel]

Luca Berra schrieb:
> On Mon, Feb 20, 2006 at 11:05:32PM +0100, Luca Berra wrote:
> to clarify:
>> you can do hot backup, but you will need to tell oracle you are doing
>> so:
>>
>> you will need to have oracle in archive log mode
>>
>> you will need to manually set all tablespaces in backup mode:
>> alter tablespace XXX begin backup; (for all tablespaces)
>> alter system switch logfile;
> the snapshot creation part goes here
> 
> NO >do your backup including the archive logs
> 
>> alter tablespace XXX end backup; (for all tablespaces)
> 
> do your backup here including the archive logs
> destroy the snapshot here.
> 
>> it is a simple sql script to code
>>
> 
Hi Mitchell, hi Luca,

well, despite i prefer using RMAN ( since 9iR2 it's once configured and 
then you can always do your backup with a simple 'backup database' ) but 
you need your database running in archived mode, which brings additional 
space and backup needs.

The way Luca describes for a online-backup is the usual way that's 
working since Oracle 7 ( or even 6, but just work with Oracle since 7.0 
;-) ), but i think, if all ( really all !) files are on the same 
snapshout and the snapshot is big enough( ;-) ), you should make a 
logswitch, create a readonly snapshot, copy all the files ( including 
control-files, and redo-logs ) and remove the snapshot. You can then 
carefully try to use these files to restore the database. If you have 
enough diskspace, you can shutdown your instance, rename all the files ( 
again incl. control-files and redo-logs ), restore the copies from the 
snapshot and start the database carefully ( startup nomount; alter 
database mount; select file#, name, status from v$datafile; -> all file 
should be in status system or online ; alter database open; -> up again ).
I have nither the time nor the resources to test this on my own. But you 
can share your results with us :-)

Ciao
Klaus


-- 
Mit freundlichen Gr�ssen / best regards

Klaus Strebel, Dipl.-Inform. (FH), mailto:klaus.strebel@gmx.net

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[linux-lvm] Situation with PVRESIZE command

[Roger Lucas]

Hi,

I am running LVM on top of a large RAID controller with a 16-drive
capability (of which just 4 disks are currently active).  The RAID array
appears as a single SCSI disk, "/dev/sda".  A quick summary of the LVM
information is below.

tiger:~# lvm version
  LVM version:     2.01.04 (2005-02-09)
  Library version: 1.01.00-ioctl (2005-01-17)
  Driver version:  4.4.0
tiger:~# pvs
  PV         VG      Fmt  Attr PSize   PFree
  /dev/sda   storage lvm2 a-   745.05G 39.05G
tiger:~# vgs
  VG      #PV #LV #SN Attr  VSize   VFree
  storage   1   3   0 wz--n 745.05G 39.05G
tiger:~# lvs
  LV   VG      Attr   LSize Origin Snap%  Move Copy%
  home storage -wi-ao 2.00G
  root storage -wi-ao 2.00G
  var  storage -wi-ao 2.00G
  main storage -wi-ao 700.0G
tiger:~# mount
/dev/mapper/storage-root on / type reiserfs (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw)
/dev/hda1 on /boot type ext3 (rw,noatime)
/dev/mapper/storage-home on /home type reiserfs (rw)
/dev/mapper/storage-var on /var type reiserfs (rw)
/dev/mapper/storage-main on /main type reiserfs (rw)
usbfs on /proc/bus/usb type usbfs (rw)
tmpfs on /dev type tmpfs (rw,size=10M,mode=0755)
tiger:~#

I now need to increase my RAID capacity.  I can increase the physical RAID
capacity by adding another disk to the controller and getting it to re-build
the array in the background, thus increasing the size of "/dev/sda", but I
am not clear as to how I can increase the PV size in LVM.  

I have seen some references to a "pvresize" command, but it isn't in the
latest 2.01.15 stable release (although it does appear in the 2.02.02
development release).

Hence, my questions are:

- Is it possible to re-size a PV whilst the system is online using the
2.01.15 tools?

- Is it possible to re-size a PV whilst the system is online using the
2.02.02 tools?

- How "stable" are the 2.02.02 tools, and are there any specific bugs in
them that may cause problems during typical usage.

Thanks,

Roger

RE: [linux-lvm] Situation with PVRESIZE command

[Roger Lucas]

Hi,

I've found Alasdair's mail from ~1 year ago on something in this area, but
it isn't quite the answer that I was looking for.

http://www.redhat.com/archives/linux-lvm/2004-December/msg00049.html

Is there anyone on this mailing list that can help with my PVRESIZE
questions below?

Thanks,

Roger


> -----Original Message-----
> From: linux-lvm-bounces@redhat.com [mailto:linux-lvm-bounces@redhat.com]
> On Behalf Of Roger Lucas
> Sent: 21 February 2006 18:01
> To: 'LVM general discussion and development'
> Subject: [linux-lvm] Situation with PVRESIZE command
> 
> Hi,
> 
> I am running LVM on top of a large RAID controller with a 16-drive
> capability (of which just 4 disks are currently active).  The RAID array
> appears as a single SCSI disk, "/dev/sda".  A quick summary of the LVM
> information is below.
> 
> tiger:~# lvm version
>   LVM version:     2.01.04 (2005-02-09)
>   Library version: 1.01.00-ioctl (2005-01-17)
>   Driver version:  4.4.0
> tiger:~# pvs
>   PV         VG      Fmt  Attr PSize   PFree
>   /dev/sda   storage lvm2 a-   745.05G 39.05G
> tiger:~# vgs
>   VG      #PV #LV #SN Attr  VSize   VFree
>   storage   1   3   0 wz--n 745.05G 39.05G
> tiger:~# lvs
>   LV   VG      Attr   LSize Origin Snap%  Move Copy%
>   home storage -wi-ao 2.00G
>   root storage -wi-ao 2.00G
>   var  storage -wi-ao 2.00G
>   main storage -wi-ao 700.0G
> tiger:~# mount
> /dev/mapper/storage-root on / type reiserfs (rw)
> proc on /proc type proc (rw)
> sysfs on /sys type sysfs (rw)
> devpts on /dev/pts type devpts (rw,gid=5,mode=620)
> tmpfs on /dev/shm type tmpfs (rw)
> /dev/hda1 on /boot type ext3 (rw,noatime)
> /dev/mapper/storage-home on /home type reiserfs (rw)
> /dev/mapper/storage-var on /var type reiserfs (rw)
> /dev/mapper/storage-main on /main type reiserfs (rw)
> usbfs on /proc/bus/usb type usbfs (rw)
> tmpfs on /dev type tmpfs (rw,size=10M,mode=0755)
> tiger:~#
> 
> I now need to increase my RAID capacity.  I can increase the physical RAID
> capacity by adding another disk to the controller and getting it to re-
> build
> the array in the background, thus increasing the size of "/dev/sda", but I
> am not clear as to how I can increase the PV size in LVM.
> 
> I have seen some references to a "pvresize" command, but it isn't in the
> latest 2.01.15 stable release (although it does appear in the 2.02.02
> development release).
> 
> Hence, my questions are:
> 
> - Is it possible to re-size a PV whilst the system is online using the
> 2.01.15 tools?
> 
> - Is it possible to re-size a PV whilst the system is online using the
> 2.02.02 tools?
> 
> - How "stable" are the 2.02.02 tools, and are there any specific bugs in
> them that may cause problems during typical usage.
> 
> Thanks,
> 
> Roger
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Re: [linux-lvm] Situation with PVRESIZE command

[Patrick Caulfield]

Roger Lucas wrote:
> Hi,


> - Is it possible to re-size a PV whilst the system is online using the
> 2.01.15 tools?
> 
> - Is it possible to re-size a PV whilst the system is online using the
> 2.02.02 tools?
> 
> - How "stable" are the 2.02.02 tools, and are there any specific bugs in
> them that may cause problems during typical usage.
> 

If you're wary of the 2.0.2 tools, then why not resize the pv using 2.02 but
leave your existing tools in place ?


-- 

patrick

RE: [linux-lvm] Situation with PVRESIZE command

[Roger Lucas]

Hi Patrick,

Thanks for the reply.

Are the different tool releases interchangable and compatible then?  If they
are, it would be a massive advantage.

- Roger

> -----Original Message-----
> From: linux-lvm-bounces@redhat.com [mailto:linux-lvm-bounces@redhat.com]
> On Behalf Of Patrick Caulfield
> Sent: 28 February 2006 13:54
> To: LVM general discussion and development
> Subject: Re: [linux-lvm] Situation with PVRESIZE command
> 
> Roger Lucas wrote:
> > Hi,
> 
> 
> > - Is it possible to re-size a PV whilst the system is online using the
> > 2.01.15 tools?
> >
> > - Is it possible to re-size a PV whilst the system is online using the
> > 2.02.02 tools?
> >
> > - How "stable" are the 2.02.02 tools, and are there any specific bugs in
> > them that may cause problems during typical usage.
> >
> 
> If you're wary of the 2.0.2 tools, then why not resize the pv using 2.02
> but
> leave your existing tools in place ?
> 
> 
> --
> 
> patrick
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Re: [linux-lvm] Situation with PVRESIZE command

[Patrick Caulfield]

Roger Lucas wrote:
> Hi Patrick,
> 
> Thanks for the reply.
> 
> Are the different tool releases interchangable and compatible then?  If they
> are, it would be a massive advantage.
> 
>

Yes, they are.

-- 

patrick

RE: [linux-lvm] Situation with PVRESIZE command

[Roger Lucas]

Wow.

I didn't think it would be that easy!  :-)

All I need to do then is to compile the latest 2.X development branch then
just use the commands that I need when I require the absolutely latest
functionality.  The "general purpose" operations can all come from the 1.X
stable branch...

Thanks for making it clear.

Regards,

Roger

> -----Original Message-----
> From: linux-lvm-bounces@redhat.com [mailto:linux-lvm-bounces@redhat.com]
> On Behalf Of Patrick Caulfield
> Sent: 28 February 2006 16:04
> To: LVM general discussion and development
> Subject: Re: [linux-lvm] Situation with PVRESIZE command
> 
> Roger Lucas wrote:
> > Hi Patrick,
> >
> > Thanks for the reply.
> >
> > Are the different tool releases interchangable and compatible then?  If
> they
> > are, it would be a massive advantage.
> >
> >
> 
> Yes, they are.
> 
> --
> 
> patrick
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/