Create a mirrored boot disk on the N Class

[Khurram Khan_1]

We are using HPUX 11.00 64bit on a N class machine, would like to create a mirrored boot disk. My understanding is that I could use the dd command to copy the boot disk to another disk and then if required can boot from the alternative boot disk. Would appreciate anyone's help on this matter, and if possible with full instructions. Thanks in advance.

Regards

Khurram

[Paula J Frazer-Campbell]

Hi

Do you wish to make a copy of the disk or do you wish to create a mirror?

Paula

[Bill McNAMARA_1]

http://forums.itrc.hp.com/cm/QuestionAnswer/1,11866,0xb5fca14d9abcd4118fef0090279cd0f9,00.html

http://forums.itrc.hp.com/cm/QuestionAnswer/1,11866,0x1a07c7af36b7d5118ff10090279cd0f9,00.html

for the dd:

http://forums.itrc.hp.com//cm/QuestionAnswer/1,,0x8aacee3e323bd5118fef0090279cd0f9,00.html

[Animesh Chakraborty]

Hi,
See the link for correct steps.
http://us-support.external.hp.com/cki/bin/doc.pl/sid=0e51423c054a593e3e/screen=ckiDisplayDocument?docId=200000055534397


Best of luck
Animesh

[Pheilon Zhou]

You may not use dd to create mirrored boot disk.
Please ensure that MirrorDisk/UX is installed in your system.

[Khurram Khan_1]

Hi Paula,

Thanks for replying back, what are the differences between the two, all we want is extra resillience so that if the primary boot disk failed then we could restart the server by booting off the alternative disk. Which methos is easier and better, would appreciate your advise.

Thanks.

Khurram

[Frederic Sevestre]

Hi,
If you want to create a mirrored boot disk :
- Install the OS on the first disk
- Then add the second disk to the vg00 :
- pvcreate -B -f /dev/rdsk/cxtydz
- mkboot /dev/rdsk/cxtydz
- mkboot -a "hpux -lq" /dev/rdsk/cxtydz (the -lq mean low quorum, you will be able to boot with only one disk)
- vgextend /dev/vg00 /dev/dsk/cxtydz
- Mirror the LV, for each LV : lvextend -m 1 /dev/vg00/lvolx /dev/rdsk/cxtydz

Regards
Fr??d??ric

[Khurram Khan_1]

Hi,

We haven't got a mirror license, and it might be a bit short notice as I need to set it up this coming Saturday. Would anyone have any thoughts on using the dd command, would that not work. Appreciate the advise, thanks.

Regard

Khurram

[Paula J Frazer-Campbell]

Hi

Safest method is to mirror the system lvols

/
/stand
/var
/usr
/tmp
/opt
/home

Ensure that you have enough space in stand for a vmuxix.bak as well as the standard vmunix.prev files.
The mirrored disks will protect each other and in the event of a disk failure the system will keep running.

Ensure that you are monitoring the disks on your system - Download and install EMS - it is free.
A vmunix.bak which should be a copy of your existing kernel can be boot from if ever the main file corrupts.
In the event of crash just boot from the /stand/vmunix.bak file.


If you do not have mirror disk then for a quick safety then at least copy all of the above directories to a second disk.

Download and install ignite which will make a bootable tape which will also enable you to recover the system.

Paula

[Santosh Nair_1]

I don't think dd'ing the disk would work. The actual physical volume used for the boot disk is stored in several place and would need to be changed on the dd'ed copy. For example, the VG information in /etc/lvmtab would point back to the original disk, the LIF area has to be updated, the lvln information has to be updated, etc. There would be too much work involved.

And even if it did work, there are still downsides to dd'ing the disk. For one thing, the two disks would be out of synch, whereas with mirroring, they're always in synch.

If you don't have Mirror/UX and can't convince your boss(es) to purchase it, I would strongly recommend that you get Ignite/UX (free download from http://www.software.hp.com/products/IUX) and install it on the machine. Then create a make_tape_recovery bootable tape. This way, if your boot/root disk crashes, you can re-install the OS on a secondary disk without having to reconfigure everything. This is still not as good as mirroring though.

-Santosh

[Michael Tully]

Hi,

Without the MirrorDisk/UX software the only
redundancy you can get with this is having a
make recovery tape standing by. Using
the dd command will never keep to the two
disks in sync even if you could get the second
disk to boot. If a problem occurred the
second disk could be build in around 1.5 hours.

HTH
-Michael

[Bill McNAMARA_1]

well dd'ing is a good option when you don't want to mirror.
Remember that mirror disk will mirror mistakes too.

The dd (or lifeboat) is a stand aside, just in case disk.

A Clay has a really good script for it, but the search engine here really sucks hard at the moment so I couldn't find his post again.

Maybe someone else will.
Ignite of course just uses a tape and not a spare disk...

Later,
Bill

[Khurram Khan_1]

Hi Frederic,

The method that you have mentioned does that require a HPUX Mirror Disk License, if yes we don't have one. Secondly how do you mirror the LV's, please send some instructions.

Thanks.

Khurram

[Frederic Sevestre]

Sorry, the mentionned method requires Mirror Disk License.
( The command to mirror the LV lvolA to the /dev/dsk/cxtydz is lvextend -m 1 /dev/vg00/lvolA /dev/rdsk/cxtydz )
Regards
Fr??d??ric

[Khurram Khan_1]

Hi,

Does anyone have any instructions on how to install and configure ignite. Secondly how do we get around replacing both the internal disks with larger disks. One of the internal disk is a boot disk, and the second one is a swap disk.

Regards

Khurram

[Sanjay_6]

Hi,

Have a look at the threads below for more info.

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90742/B2355-90742_top.html&con=/hpux/onlinedocs/B2355-90742/00/00/49-con.html&toc=/hpux/onlinedocs/B2355-90742/00/00/49-toc.html&searchterms=Managing%20Mirrored%20File%20Systems%20%20&queryid=20011025-065545

Look for "Managing File Systems "---> "Managing Mirrored File Systems " -->"Mirroring Root, Boot, and Primary Swap Logical Volumes "

http://us-support2.external.hp.com/cki/bin/doc.pl/sid=621f750d1de451cef1/screen=ckiDisplayDocument?docId=200000055534397

Hope this helps.

thanks

[Frederic Sevestre]

HP-UX Installation Utilities (Ignite-UX) doesn't need to be configured. You just have to install it on your server using swinstall.
To change the both internal disks, you should make a bootable recovery tape using ignite (man make_recovery), change your disks, boot on the tape and reinstall the server using it.
Regards

[Khurram Khan_1]

Hi,

Can someone point me to the correct URL to download IGNITE, as I will be looking at this option.

Thanks.

Khurram

[Paula J Frazer-Campbell]

Hi
Ignite here, as many have said this is free and will enable you to recover your system.

http://www.software.hp.com/products/IUX/download.html

Do not forget to assign points to the many good answers that you have received on this.

Paula

[Fred Myers]

You could do this it is not as safe but it works as well, plus you can bring it up and resync it whenever you want!

- Install the OS on the first disk
- Then add the second disk to vgalt :
- pvcreate -B -f /dev/rdsk/cxtydz
- mkboot /dev/rdsk/cxtydz
- mkboot -a "hpux -lq" /dev/rdsk/cxtydz (the -lq mean low quorum, you will be able to boot with only one disk)
- vgcreate /dev/vgalt /dev/dsk/cxtydz
- then do some lvcreate's with the logical volume numbers the same and mount on /aroot /ausr . . . . etc. then you can do a

cd /(whatever)
find and pipe to cpio for a copy
then unmount the filesystems, you can now boot off the secondary disk by updateing your set_boot parms to make it alt.

BTW I highly suggest you beg your company to buy mirror disk UX it is by far the best methode for data integrity.

[Michael Tully]

Hi,

You can download ignite from the URL as
already mentioned, but you should have a
copy of it on the 1st CD of your
application CD set. It is product No
B5725AA -->HP-UX Installation Utilities

Once installed by using 'swinsta' you can easily create a tape by issuing this command.

# make_tape_recovery -x inc_entire=vg00 -I -v -a /dev/rmt/0mn

Make sure that you use the no rewind device.

-Michael

[Khurram Khan_1]

Hi,

Thanks for all the replies I have recieved from everyone, there is another question i.e. we don't have a internal tape drive. We only have two external DLT drives attached to the N4000, will the make_tape_recovery command still work and check the DLT drive(s) and tape when it boots up.

Secondly what would I need to do if the tape recovery process works, i.e once booted up with tape what do we need to do get everything back onto the boot disk etc.


Regards



Khurram

[Michael Tully]

Hi,

I am fairly sure that you cannot create a bootable image on a DLT drive. I will stand corrected if it can be done.

-Michael

[Christopher McCray_1]

I am not sure if you can use a DLT as a bootable device, however, it is possible to create an "ignite server" on one of your other servers, which may be something to explore. The bottom line is, you need to get something, like Ignite, or MirrorDisk. Granted, MirrorDisk costs a pretty penny, but you are safe from most failings that may occur with your disks. If the ignite server isn't an option, you should get a DDS drive installed. They really aren't that expensive when considering the cost involved with a system crash and no way to recover.

Hope this helps and good luck.

Chris

[Dave Echols]

DLT devices are now OK to use for make_tape_recovery purposes on certain systems including N class servers.