LSM swap space science

From: Markus Waldorf <waldorfm_at_rferl.org>
Date: Tue, 01 Jul 2003 20:59:09 +0200

Hello,

I have to admit that LSM has not done a very good job so far to make me more
comfortable with what I'm doing. I've been playing around with LSM for
weeks, and I better not mention how many times I decided to start over and
over again. I've been going through the documentation, best practices and
mailing lists items, but I'm still searching for some clear answers. I
believe having the filesystems configured properly is not a trivial issue,
in particular LSM. Readme later.

I'm searching for answers how to properly setup LSM swap space. So far I've
come to the following conclusions. I go somewhere, but perhaps someone could
let me know if I'm at the right place.


1) swap volumes must belong to the rootdg disk group and must be nopriv
disks - at least according to "volencap". The volencap command can be used
to "encapsulate" a disk (whatever that means), or in other words, it makes
nopriv disks and creates LSM volumes. Where disk can be a whole disk or just
a partition.

For example, I created partitions dsk4b, dsk5b, all type unused, and want to
use or prepare them for LSM swap mirror:

# volencap dsk4b dsk5b
# volreconfig

The above will automatically create plexes and nopriv LSM volumes in the
rootdg group. But what about swap space parameters? I cannot use the LSM GUI
to change the volumes to these parameters, even if the volumes are stopped -
it results just in errors about bad parameter combinations.


2) I was reading that swap space should be set no "no recover" and "no log".
So I did the following in order to manually remove volumes from LSM and
create them using command-line tools:

>From the LSM gui advanced menu:

- working on dsk4b
- select volume, volume stop
- select plex (big box) and move it off the volume
- select volume (now empty) and use remove volume from the menu

I don't like the default names so I right-click on the plex and the subdisk
in order to make it more meaningful, e.g. dsk4b: Plex swapvol05-01, subdisk:
swap05-01.

Than I issued the following commands to create a new volume named swapvol03
with the desired options:

# volmake -U swap vol swapvol03 plex=swapvol05-01 log_type=NONE
# volume set start_opts=norecov swapvol03

I want to mirror dsk4b and dsk5b, so back in LSM gui:

>From the LSM gui advanced menu:

- working on dsk5b
- select volume, volume stop
- select plex (big box) and move it off the volume
- select volume (now empty) and use remove volume from the menu
- select subvolume within plex and move it off with the mouse
- select plex and remove it
- select subvolume on disk and remove it

- select swapvol03 and middle-click dsk5b
- from the basic LSM gui menu select add mirror
- wait for it to complete
- rename the subdisk and plex by right-clicking them



Well, it seems to work, but what It adds another subdisk to each of the the
swapvol03 plexes. Is that ok? I did not see this when using ie. "volrootmir"



Here is a volprint:

# volprint -htl swapvol03
Disk group: rootdg

Volume: swapvol03
info: len=8912896
type: usetype=swap
state: state=ACTIVE kernel=ENABLED
assoc: plexes=swapvol05-01,swapvol03-01
policies: read=ROUND exceptions=GEN_DET_SPARSE
flags: closed writeback
logging: type=NONE
apprecov: seqno=0
device: minor=1 bdev=40/1 cdev=40/1 path=/dev/vol/rootdg/swapvol03
perms: user=root group=system mode=0600
options: norecov

Plex: swapvol05-01
info: len=8912896
type: layout=CONCAT
state: state=ACTIVE kernel=ENABLED io=read-write
assoc: vol=swapvol03 sd=swap05-01p,swap05-01
flags: complete

Subdisk: swap05-01p
info: disk=dsk4b offset=0 len=16
assoc: vol=swapvol03 plex=swapvol05-01 (offset=0)
flags: enabled (nullwr)
device: device=dsk4b path=/dev/disk/dsk4b diskdev=81/257

Subdisk: swap05-01
info: disk=dsk4b offset=16 len=8912880
assoc: vol=swapvol03 plex=swapvol05-01 (offset=16)
flags: enabled
device: device=dsk4b path=/dev/disk/dsk4b diskdev=81/257

Plex: swapvol03-01
info: len=8912896
type: layout=CONCAT
state: state=ACTIVE kernel=ENABLED io=read-write
assoc: vol=swapvol03 sd=dsk5b-01p,dsk5b-01
flags: complete

Subdisk: dsk5b-01p
info: disk=dsk5b offset=0 len=16
assoc: vol=swapvol03 plex=swapvol03-01 (offset=0)
flags: enabled (nullwr)
device: device=dsk5b path=/dev/disk/dsk5b diskdev=81/321

Subdisk: dsk5b-01
info: disk=dsk5b offset=16 len=8912880
assoc: vol=swapvol03 plex=swapvol03-01 (offset=16)
flags: enabled
device: device=dsk5b path=/dev/disk/dsk5b diskdev=81/321

# volprint -hlt swapvol03
Disk group: rootdg

Volume: swapvol03
info: len=8912896
type: usetype=swap
state: state=ACTIVE kernel=ENABLED
assoc: plexes=swapvol05-01,swapvol06-01
policies: read=ROUND exceptions=GEN_DET_SPARSE
flags: closed writeback
logging: type=NONE
apprecov: seqno=0
device: minor=1 bdev=40/1 cdev=40/1 path=/dev/vol/rootdg/swapvol03
perms: user=root group=system mode=0600
options: norecov

Plex: swapvol05-01
info: len=8912896
type: layout=CONCAT
state: state=ACTIVE kernel=ENABLED io=read-write
assoc: vol=swapvol03 sd=swap05-01p,swap05-01
flags: complete

Subdisk: swap05-01p
info: disk=dsk4b offset=0 len=16
assoc: vol=swapvol03 plex=swapvol05-01 (offset=0)
flags: enabled (nullwr)
device: device=dsk4b path=/dev/disk/dsk4b diskdev=81/257

Subdisk: swap05-01
info: disk=dsk4b offset=16 len=8912880
assoc: vol=swapvol03 plex=swapvol05-01 (offset=16)
flags: enabled
device: device=dsk4b path=/dev/disk/dsk4b diskdev=81/257

Plex: swapvol06-01
info: len=8912896
type: layout=CONCAT
state: state=ACTIVE kernel=ENABLED io=read-write
assoc: vol=swapvol03 sd=swap06-01p,swap06-01
flags: complete

Subdisk: swap06-01p
info: disk=dsk5b offset=0 len=16
assoc: vol=swapvol03 plex=swapvol06-01 (offset=0)
flags: enabled (nullwr)
device: device=dsk5b path=/dev/disk/dsk5b diskdev=81/321

Subdisk: swap06-01
info: disk=dsk5b offset=16 len=8912880
assoc: vol=swapvol03 plex=swapvol06-01 (offset=16)
flags: enabled
device: device=dsk5b path=/dev/disk/dsk5b diskdev=81/321

#
Received on Tue Jul 01 2003 - 18:59:57 NZST

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