Veritas-bu

[Veritas-bu] rad5 and disk wastage

2005-11-16 10:36:58
Subject: [Veritas-bu] rad5 and disk wastage
From: ddunham AT taos DOT com (Darren Dunham)
Date: Wed, 16 Nov 2005 07:36:58 -0800 (PST)
> Question #1
> #vxassist -g brpcdr_dg make cdr01 10g layout=3Draid5 brpcdr_01 brpcdr_02
> brpcdr_03 brpcdr_04
> #vxassist -g brpcdr_dg maxgrow cdr01 brpcdr_01 brpcdr_02 brpcdr_03 brpcdr_0=
> 4
> #vxresize -g brpcdr_dg cdr01 279976m brpcdr_01 brpcdr_02 brpcdr_03 brpcdr_0=
> 4

This is a general volume manager question not a netbackup one.  You
should send questions like this to veritas-vx, not veritas-bu.

By default, a layout=raid5 volume will create a log, and that log will
be located on a disk that does not contain any other raid5 data.  So
with 4 disks you have one basically unused except for the log, and then
3 other disks used.

>  As I create the file system on the cdr01 its only of 269GB. But I think it
> should be around 3*136=3D408 why it is so?

Because the log disk limits it.  You can either try to force the log
onto some of the disks used for data, or you can create the raid5 with
no log to save space.   The first might have a performance hit with the
head seeking around, the second is more vulnerable to certain failures.  

>  Question #2
>  How can I merg the above two commands into one command?

You have three commands above.  You can merge them into two...

# vxassist -g brpcdr_dg maxsize layout=raid5,nolog brpcdr_01 brpcdr_02 
brpcdr_03 brpcdr_04
# vxassist -g brpcdr_dg make cdr01 <size> layout=raid5,nolog brpcdr_01 
brpcdr_02 brpcdr_03 brpcdr_04

-- 
Darren Dunham                                           ddunham AT taos DOT com
Senior Technical Consultant         TAOS            http://www.taos.com/
Got some Dr Pepper?                           San Francisco, CA bay area
         < This line left intentionally blank to confuse you. >

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