[rescue] Solaris filesystem overview, comparison to HP/IBM
rawallis at panix.com
Sat May 20 10:24:20 CDT 2006
On May 20, 2006, at 12:41 AM, Eric Webb wrote:
> We're about to purchase a few additional Sun systems at $work and I
> need a
> refresher on Solaris disk/filesystems past and present. The
> application requires Solaris 9 for whatever reason, so I cannot
> some of the newer stuff (ZFS) I've read about in Solaris 10. We'd
> like to
> end up with a Sol 9 environment with JFS reliability and LVM
> ease-of-management (including online filesystem resizing/expenasion.)
> I would appreciate any comparisons you can give to features of IBM
> AIX (JFS +
> LVM) and HP-UX (vxfs + MirrorDisk/UX + Online JFS) that I am more
> with... LVM versus slices/md.... JFS versus UFS versus whatever
> else is
The AIX LVM is my favorite LVM because it is the most sane and
easiest to deal with. It is very trivial to add another disk to a
volume group and increase filesystem sizes on the fly. I love the
fact that one could increase the filesystem while it was mounted and
being written to. I haven't run into the issue of hitting the
physical partition count limit, but it does exist. One of the big
disadvantages to AIX is that volume groups other than rootvg are not
saved as part of a mksysb. We always run savevg commands to dump the
rest of them to a tape after the rootvg backup record on a tape.
I'll state bluntly that the HP-UX LVM subsystem sucks royal donkey
balls. One of my favorite pet peeves for it was that one had to hunt
for an available major/minor number for a volume group.
Solstice DiskSuite doesn't have a concept of a volume group, but that
could be faked through a large metadevice with soft partitions in
it. You can still grow filesystems while they are mounted (through
metattach and growfs), but Sun makes it clear that the filesystem is
read-only during the grow. HP-UX, AIX, and Solaris all can put root
into a logical volume. AIX is the only one to do it natively because
all it deals with are LVs. It has no concept of a disk-based
filesystem that is not controlled by LVM. I've haven't played with
metaroot much in Solaris or HP-UX.
UFS with logging is close enough to JFS to be the same. The only
difference is that Solaris doesn't have log commands to
replay,reform, or delete a log during system recovery.
I haven't played with Solaris Flash archives, which came with Solaris
8, so I can't speak to it for system restores with metadevices. We
used a homegrown mksysb knockoff to backup and restore Solaris
system. When I updated it for Solstice DiskSuite, I ran into a couple
of errors that Sun would not fix until Solaris 10. The biggest was
using metainit -a on a md.tab file to recreate a SVM environment.
While the documentation said that it could be used, DiskSuite would
not recreate soft partitions that were listed. The result was that
you have to explicitly recreate each metadevice to insure a proper
My workplace encapsulated the Solaris /var and /usr into slice based
metadevices and created a nice RAID 1 to a second drive on SB100/
SB150 workstations and 280Rs. They worked nicely for either drive
failed. Our architects fell in love with giving home grown
applications their own metadevice filesystems rather than using
quotas. It became trivial to add space to fielded systems when log
processing or system management tools needed more room for work.
> I remember that Sun added certain features (if not whole products,
> like Disk
> Suite, no?) to previous Solaris releases... maybe Sol7 or Sol8...
> and I'm
> curious to fill the voids in my historical knowledge.
Solaris 9 was when Sun took Solstice DiskSuite 4.2.1 (with the soft
partition patch) and added it to the baseline OE. Previously, it was
a costly add-on. It was then renamed Solaris Volume Manager.
DiskSuite 1.0 started back in the SunOS 4 days. I believe that Bill
and some others used it back then.
Veritas is a very expensive LVM that I wanted to throttle because it
can't be completely automated. We couldn't use it during our
automated restores because it will not run at all without a valid
license key. A reinstall even on the same machine would force you to
call Vertias to relicense the machine. Imagine doing this for a test
lab of 20-30 machines that would be reinstalled several times each
shift to see how quickly our patience ran out with VxVM. Its
installation is also very difficult to automate. The Sun Blueprint
book for Jumpstart devoted an entire chapter to it as an example of
installing troublesome 3rd party software in a Jumpstart session.
More information about the rescue