Max Chunk Size
MS CARLEEN C AVANT
Question regarding Informix 2GB max chunk size. We are configuring a 7.2x
environment (probably will be 7.22 and definitely on a Sun Enterprise
4000). We have about 14 production databases. We will be working with 6 x
4.2 GB of space. We have always been under the assumption that it was
better to isolate each database to it's own dbspace so we can better
"control" each database. However that means alot of "carving" of space. It
was then suggested to us that we should configure max chunk size for all
the disk space and basically put all databases out there (of course being
aware of what goes where for performance reasons) creating each dbspace
containing a 2GB chunk and several databases per dbspace.
Can anyone offer good, sound arguments in favor of one or the other? We
appreciate any helpful information offered.
Carleen Avant Code 54b
Internet < cav...@safecen.navy.mil >
COM (757)444-3520 DSN 564-3520
ext 7050
David Williams
In article <61jald$3...@cssun.mathcs.emory.edu>, MS CARLEEN C AVANT
<cav...@safecen.navy.mil> writes
>Question regarding Informix 2GB max chunk size. We are configuring a 7.2x
>environment (probably will be 7.22 and definitely on a Sun Enterprise
>4000). We have about 14 production databases. We will be working with 6 x
>4.2 GB of space. We have always been under the assumption that it was
>better to isolate each database to it's own dbspace so we can better
>"control" each database. However that means alot of "carving" of space. It
>was then suggested to us that we should configure max chunk size for all
>the disk space and basically put all databases out there (of course being
>aware of what goes where for performance reasons) creating each dbspace
>containing a 2GB chunk and several databases per dbspace.
>Can anyone offer good, sound arguments in favor of one or the other? We
>appreciate any helpful information offered.
>
>
1 dbspace = 1 chunk = 1 2Gb disk.
Since your fragment at the dbspace level this allows you to easily
fragment across disks...
>
>
>Carleen Avant Code 54b
>Internet < cav...@safecen.navy.mil >
>COM (757)444-3520 DSN 564-3520
> ext 7050
--
David Williams
Koen Van der Elst
Spreading your db's across chunks gives you a performance advantage. Because
Informix can do A LOT of things in parallel using its multi-threaded
achitecture, most operations will go A LOT faster.
Check your Administrators Guides and the Performance Guide.
Watch out with Sun's array controller. The software that comes with it (vxva
it think it is called) does not allow you to partition you disks.
Eg: Say you have 10 disk of 4GB and you configure them using RAID1 (forget
RAID5 when using Informix). You will end up with 4 logical volumes of 4 GB
and no possibility to partition them!
Because the maximum chunck size in Informix is 2 GB, you have a problem!
Solstice does not have this problem but is does not support the array
controller. Bummer.
One nice thing though: that machine literaly flies using Informix. I've been
working with an Enterprise Server 3000 and it kicks ass!
K.