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LSM MIRRORING

chintan_1
Occasional Contributor

LSM MIRRORING

I have four disks of 9.1GB & i want to mirror the disks using LSM , presently four disks are configured under rootdg. How do & remove the four disks & configre two mirror. My O/S is Tru64 4.0D

Regards
Chintan Upadhyay
chintan.upadhyay@gmail.com
7 REPLIES

Re: LSM MIRRORING

Hey Chintan,

First we need to know what those disks are going. Do you have LSM volumes on each of the disks or any volumes than span disks? I ask because before we can create a new plex, we have to evacuate any data from the mirror devices that would be lost.

A volprint would be helpful in sorting out what you need to do.

There's several ways to do it, including making a plex by hand using volmake or using volassist to mirror. After we have an idea of how rootdg is presently configured, you probably can just get away with:

volassist -b move !

to get everything on two disks, then

volassist mirror

to create the mirrors for each volume on the other two disks.

Jack
chintan_1
Occasional Contributor

Re: LSM MIRRORING

Hi Jack

Thanks a lot for your inputs,please note that presently 04 disks of 9.1GB is configured under rootdg & we want to make two mirror (02 disk each). The volprint details are as follows.
----------------------------------
O/P of command volprint -ht


DG NAME GROUP-ID
DM NAME DEVICE TYPE PRIVLEN PUBLEN PUBPATH
V NAME USETYPE KSTATE STATE LENGTH READPOL PREFPLEX
PL NAME VOLUME KSTATE STATE LENGTH LAYOUT ST-WIDTH MODE
SD NAME PLEX PLOFFS DISKOFFS LENGTH DISK-NAME DEVICE

dg rootdg 1152011207.1025.alpharil1

dm rz10 rz10 sliced 1024 17772484 /dev/rrz10g
dm rz11 rz11 sliced 1024 17772484 /dev/rrz11g
dm rz12 rz12 sliced 1024 17772484 /dev/rrz12g
dm rz13 rz13 sliced 1024 17772484 /dev/rrz13g
------------------------------------------
O/P of command volprint -Gt


DG NAME GROUP-ID

dg rootdg 1152011207.1025.alpharil

Re: LSM MIRRORING

Hey Chintan,

Ok, I should have been more specific, but this is helpful. What I need to see if the output of
volprint -Aht

so I can see the volume(s) inside rootdg and what subdisks they are on so I can give you precise commands syntax.

In essence, once we know what the names of the volumes are, and what the subdisk and plex names are, we can just use volassist to move everything onto a plex comprised of two disks and make a new plex (another name for a "mirror") out of the other two disks. It won't be hard, and with a max of 18gb to move around, it won't take too long to actually do but we have to get the syntax just right or it won't work at all.

Jack

Re: LSM MIRRORING

Ugh, my bad. I didn't read what you posted carefully, I just scanned quickly for volume names and didn't see any. You DID post output from volprint -ht which is fine since you only have rootdg under LSM control.

I apologize.

I forgot we were working with LSM 4 here so things a just a little bit different. OK, I'm going to post again here in a few minutes with a procedure here but I wanted to post this apology before some other LSM guru flames me ;-)

It looks like you've pretty much just got the disks encapsulated and that's it. That's just fine, we can work with that.

I'm guessing at this point, you can do
voldctl list
and you get some output about the Volboot file that has your 4 disk devices listed.
and if you do
voldctl mode
you'll get "enabled"
At this point you can plex away. I'll post how in just a minute

Jack

Re: LSM MIRRORING

after racking my brain to remember older LSM commands, I remembered that

volprint -htv

is the syntax which will show volumes. Can you run that for me and post the output? You could probably just show me:

ls /dev/vol/rootdg

too, but the LSM command is more meaningful and accurate for generating the volassist commands.

Thanks, and sorry for the confusion, I'm a bit rusty with LSM on 4.0d

Re: LSM MIRRORING

ok Chintan, I promise I'm going to get my ramblings under control...

We didn't discuss what filesystem you're going to put on the volume under LSM control, but I'd strongly suggest AdvFS especially if you have a license for the AdvFS utilities.

Until you have a chance to post the volprint -htv output, here's a little info to tide you over:

Basically, what we're going to do is organize your 18gb volume onto a plex (think "mirror") which consists of two subdisks, which for convenience's sake, we'll designate as rz10 and rz11. Then, we'll make another plex out of rz12 and rz13 and attach it to the volume, which will automagically create the software raid 0 protection you want for the diskgroup. For performance's sake, consider making the plexes striped. The third procedure below shows you how.

1). USING VOLMAKE (concat plexes):
These commands create the subdisks:

# volmake sd <1st subdisk name> rz10,0,9g
# volmake sd <2nd subdisk name> rz11,0,9g
# volmake sd <3rd subdisk name> rz12,0,9g
# volmake sd <4th subdisk name> rz13,0,9g

*NOTE* offset will probably be 0 and size the max size of the disk (9gig) since it looks like you initialized the whole disks and not just some partition. You can give it any subdisk name you want, it's just a mnemonic and doesn't really mean anything to LSM until you specify it in a modification command

This creates two plexes and associates two subdisks to each (18gb):
# volmake plex <1st plex name> sd=<1st sd> <2nd sd>
# volmake plex <2nd plex name> sd=<3rd sd> <4th sd>

This creates the volume and attaches the plexes to it:
# volmake vol plex=<1st plex name>,<2nd plex name> usetype=fsgen

Then start the volume:
# volume start

Just to make sure, check the the volume construction:
# volprint -ht


2). USING VOLASSIST (concat plex):
This will make an 18 gig volume out of rz10 and rz11 and start it:

# volassist make 18g rz10 rz11

This will create the second plex (or "mirror") for your volume and attach it:

#volassist mirror rz11 rz12

3). MIRRORED AND STRIPED VOLUME:
This demonstrates a bottom-up approach to creating a new mirrored volume, with plexes striped across two subdisks for better I/O.

The following command creates the subdisks, I just picked an arbitrary name for each:
# volmake sd 1st-sd rz10,0,9g
# volmake sd 2nd-sd rz11,0,9g
# volmake sd 3rd-sd rz12,0,9g
# volmake sd 4th-sd rz13,0,9g

Creates the plexes:
# volmake plex 1st-pl sd=1st-sd,2nd-sd layout=stripe stwidth=16k

# volmake plex 2nd-pl sd=3rd-sd,4th-sd layout=stripe stwidth=16k

Create the volume:
# volmake -U gen vol my_volume plex=1st-pl, 2nd-pl

The following command starts the volume:
# volume start my_volume

Display the config:
# volprint -ht my_volume

That's about it. For adding filesystems, check the advfs man page but I'm sure you already know how to do that.

I'd suggest that if you need more granulatity in storage management that you create more than one volume and place a single AdvFS filesystem in each. You'll take a little performance hit maybe with the LSM overhead, but it won't be much and you'll thank yourself for the extra organization if you ever have a failed disk.

Jack
chintan_1
Occasional Contributor

Re: LSM MIRRORING

Hi Jack

Please find the O/P of volprint -Aht
------------------------------

Disk group: rootdg

DG NAME GROUP-ID
DM NAME DEVICE TYPE PRIVLEN PUBLEN PUBPATH
V NAME USETYPE KSTATE STATE LENGTH READPOL PREFPLEX
PL NAME VOLUME KSTATE STATE LENGTH LAYOUT ST-WIDTH MODE
SD NAME PLEX PLOFFS DISKOFFS LENGTH DISK-NAME DEVICE

dg rootdg 1152011207.1025.alpharil1

dm rz10 rz10 sliced 1024 17772484 /dev/rrz10g
dm rz11 rz11 sliced 1024 17772484 /dev/rrz11g
dm rz12 rz12 sliced 1024 17772484 /dev/rrz12g
dm rz13 rz13 sliced 1024 17772484 /dev/rrz13g

Regards
Chintan Upadhyay