[Veritas-vx] Volume type different
doug at eng.auburn.edu
Wed Feb 12 23:09:43 CST 2003
On Thu, 13 Feb 2003, nawir wrote:
> Hi expert,
> I want to know what is the difference between volume #1 (see below) and volume #2 in terms of volume type and advantage/disadvantage
> Volume #1 is created by me that I know exactly I am using concatenate pro while the other one is not by me.
> 1. Volume with ConcatePro
> v hroracle - ENABLED ACTIVE 10485760 SELECT - fsgen
> pl hroracle-03 hroracle ENABLED ACTIVE 10485760 CONCAT - RW
> sv hroracle-S01 hroracle-03 hroracle-L01 1 10485760 0 4/4 ENA
> v hroracle-L01 - ENABLED ACTIVE 10485760 SELECT - fsgen
> pl hroracle-P01 hroracle-L01 ENABLED ACTIVE 10485760 CONCAT - RW
> sd hrorada02-02 hroracle-P01 hrorada02 0 10485760 0 c1t3d1 ENA
> pl hroracle-P02 hroracle-L01 ENABLED ACTIVE 10485760 CONCAT - RW
> sd hrorada04-02 hroracle-P02 hrorada04 0 10485760 0 c1t3d3 ENA
> 2. Volume not created by me
> v oracle - ENABLED ACTIVE 8388608 SELECT - fsgen
> pl oracle-01 oracle ENABLED ACTIVE 8388608 CONCAT - RW
> sd disk02-04 oracle-01 disk02 46137344 8388608 0 c3t2d1 ENA
> pl oracle-02 oracle ENABLED ACTIVE 8388608 CONCAT - RW
> sd disk04-03 oracle-02 disk04 20971520 8388608 0 c3t2d3 ENA
a concat-pro volume is 1+0. it is more resilient in the face of failure.
You can lose 1 disk from each mirrored pair and keep running.
volume 2 is 0+1, you can lose one or more disks from one side (plex)
In this specific case there is no advantage to 1 because there
are only 2 disks. In fact, there is a slight disadvantage because
growing it is a bit more difficult to do in an understandable fashion.
For simple mirrors, use 0+1. Then you can grow it (and convert
to a 1+0 later) easier, in an understandable and easily viewable
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