Volume Managers

[Sonison James]

Hello All,

I would like to know what Volume Managers are available apart from LVM. For these, I would like to know about the APIs (or commands) that

1. Gets the file system free space
2. Lets me determine which file system maps to which physical drive.

Thanks and regards
Sonison James

[Michael Tully · Accepted solution]

LVM comes as part of the standard operating system. It does however, have two add-on modules, one being MirrorDisk/UX and OnLine-JFS. (These two are not free)

The other volume manager you've probably heard is called VxVm. This is an add on product from Veritas.

As far as your questions are concerned:

1) bdf which shows file system stats from mounted filesystems. You can also use 'vgdisplay -v /dev/vgxx' to get other stats.
2) Using the output from 'pvdisplay' you can track what logical volume is on each physical LUN. You can then map these logical volumes from bdf and /etc/fstab.

[Sonison James]

Hello Michael,

Thanks for the information, however I was looking for information about storage managers that use SDS or hard partitions ( or others ).

Thanks and regards
Sonison James

[Jean-Louis Phelix]

Hi,

1 - you could have a look at 'statfs' or 'statfsdev' which are C APIs to build something like a bdf

2 - Not so easy in fact ... Especially with stripped or distributed lvols. Don't really know APIs, but if pvdisplay works quite well for LVM, I remember that it was one of my big fears about VxVm. Finding where data really is when You use plex, mirror, distribution and so on. I thougth it was almost impossible :-)

Regards.

[Bill Hassell]

If SDS refers to Software Disk Striping for HP-UX, this has been obsolete for many years. And as for full disk mountpoints (without using LVM), most sysadmins who have tried them have been burned bigtime when using tools like Ignite/UX or performing an upgrade. LVM is by far the simplest method to manage disk space and contrary to rumors, does not introduce any meaningful overhead into disk access time.

As mentioned, bdf will answer all the questions about device files versus filesystems. To see a physical path, use pvdisplay and lssf to see the physical location of a specific disk.

[Sonison James]

Hello,

Thanks for the information. This has been really helpful as I wanted to know of the possibilities before attempting it.

Thanks and regards
Sonison James