SUMMARY : Adding disks to a RAIDSET

From: Jorge Grijalba (jgrijalba@novasoft.es)
Date: Tue Jan 28 2003 - 10:42:22 EST

• Next message: Taylor, Garry: "LSI / STK Disk"
• Previous message: Brewer, Edward: "Uptime clarification"
• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]

 Thanks you to :

        Rich Glazier
        A. Mahendra Raja
        Christian Wessely
        Bruce Hines
        Michael James Bradford

 for their replys.

Original question:

"Admins,

        I've a RAID with three physical disks as a RAIDSET. From Command Console
( from Storage Works ) I can see that I have only one volume 'D100' belongs
to an only one Container called 'RAIDS0'.
        The hosts are two Alpha1200 with Digital UNIX Tru64 V4.0d . They are in
cluster with ASE (Available Server Enviroment) v. 1.5.
        The hosts sees the volume as a partitioned volume called 'rrz17' with eigth
partitions : 'rz17a','rz17b', 'rz17c'... and so on.
        I want to add three physical disks more and I want to configure them as a
RAIDSET.
        All the actual volume's partitions are used in the host as raw partitions
except one
that is used as an Advanced File System and the use for the new volume would
be the same.
        I've read that it's difficult to add new disks to an existing RAIDSET.
Then it seems better to create a new RAIDSET. What are the dissavantages of
creating a new RAIDSET ? "

I choose part of the reply from Michael:

"It is impossible to add disks to an existing raidset.

The disadvantage in creating a new raidset (with three new disks) is that
you "lose" one third of the raw disk space. If thisis not acceptable, backup
up your data, destroy the existing raidset and create a new one with all six
disks. This will mininise the "lost" space. The data can then be restored. "

and this from Bruce Hines

"Assuming your existing RAIDset is located across multiple buses (ie, RAIDS0
is made up of DISK10..., DISK20... And DISK30... Or similar) and the new set
will be across multiple buses, then you should experience about the same
performance. It does give you flexibility with another disk seen by the
host to make use of the partitions. That is, if you need more space in your
AdvFS you can just add another volume (one of the new partitions) and etc.."

Regards,

        Jorge Grijalba

• Next message: Taylor, Garry: "LSI / STK Disk"
• Previous message: Brewer, Edward: "Uptime clarification"
• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]

This archive was generated by hypermail 2.1.7 : Sat Apr 12 2008 - 10:49:05 EDT