Mapping Solaris Volume Manager terms to LVM terms.
By user12610379 on May 20, 2005
People who are
familiar with LVM, LVM2 (from Linux) might find the
Solaris Volume Manager terms a bit strange. So here's a
cheat sheet. It is by no means complete. But it should get you started.
Volume Group = diskset
PE = soft partition on a slice
LE = soft partition on a metadevice
mirror = RAID 1 (it is really RAID 0+1 but works as 1+0) (/dev/md?)
raid = RAID 5
hotspare = could not find that concept in Linux
All Solaris Volume Manager commands begin with meta. This naming convention came from a device view perspective. RAID 0, RAID 1(0+1 and 1+0) RAID-5, soft partitions are all different types of metadevices. Solaris Volume Manager can operate either or slices or an entire disk. To quickly get started you can look up the documentation. I like this layout since it is organized as tasks.
My quick comparison with LVM/LVM2 indicates that the Solaris Volume Manager is quite a bit more sophisticated. It is more in line with the functionality provided by EVMS or VxVM. To get started, it might be useful to look at the overview here
Manager supports 32 disksets. In each diskset, 8192
metadevices can be created. Prior to Solaris 10, /kernel/drv/md.conf
had variables nmd and
md_sets. These variables controlled the number of metadevices and
the system. The default values for nmd was 128 and md_sets was 4. If
wanted to create more than 128 metadevices, you would have to change
and reboot!! Gawd..you blew your 5 nines right there!
In S10, we eliminated the need for these variables. Now one can go to
maximum without any tuning.
Storage is grouped in disksets. The default diskset is referred to as the local set (i.e. diskset 0). All other disksets are called named disksets. When multiple nodes are connected to common storage, it must be managed in a named diskset. These named disksets can have either a single owner or multi-owners. The single owner diskset is equivalent to the private container concept in EVMS. Multi-owner disksets provide cluster volume management functionality. This is similar to the shared container concept in EVMS. Unlike EVMS, Solaris Volume Manager supports, mirroring in a shared environment. A more detailed overview of the disksets is available here