Hello all managers !
Here is a brief summary of the responses I got from my questions about LSM
and it's possibilities/restrictions and advantages/disadvantages.
Thanks to the people who replied:
Jean-Pierre Lamarche (lamarcjp_at_sidoci.qc.ca)
David Warren (warren_at_atmos.washington.edu)
Craig I. Hagan (hagan_at_oec.com)
alan_at_nabeth.cxo.dec.com
Paul E. Rockwell (rockwell_at_rch.dec.com)
(:-)
Summary:
1. LSM organises disks/partitions in volumes and is thus a utility ala LVM
(Logical Volume Manager) but with extended functionality and robustness
(according to the DEC people). LSM lacks some of the usual disk i/o
controls but otherwise you can access LSM volumes through block/character
devices as with ordinary disks. If you organise your disks in LSM volumes
you have the striping/mirroring abilities and a GUI interface (if you
purchase a full LSM license). LVM has the capability of mirroring logical
extents in a logical volume but cannot mirror on the volumegroup level (LVM
is a non-licensed product and scheduled for retirement, but I don't know
when).
To grow a LSM volume and expand the filesystem(s) already created on it you
have to backup and recreate the filesystem(s) if you don't have the
'extendfs' command. AdvFS on top of LSM in the current release (3.0) cannot
do this without backing up/recreating/restoring (please correct me if I'm
wrong).
2. AdvFS is a FILE SYSTEM type like UFS, CDFS etc., but has some of LSM's
capabilities incorporated (e.g the volume concept). It is also log-based
and is designed for fast recover, increased consistency and greater
flexibility and manageability. You cannot access AdvFS through
character/block devices. You cannot stripe/mirror AdvFS volumes. If you
want striped/mirrored volumes, you must first create a LSM volume, then
incorporate that volume into a AdvFS file system. AdvFS volumes can be
created/added/removed on the fly assuming that the AdvFS is a multi volume
domain.
The extended utilities in AdvFS (adding volumes to an existent domain,
cloning, balancing, a GUI etc.) is licensed.
If someone feel like commenting/correcting, please do. I'll repost a
rectified summary.
--
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* Knut Helleboe | DAMN GOOD COFFEE !! *
* Norsk Hydro a.s | (and hot too) *
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Received on Mon Jan 30 1995 - 14:16:13 NZDT