Best file system type for databases

Best file system type for databases

Post by Rick Denoir » Sat, 30 Nov 2002 08:25:01



I am in the process of setting up an Oracle DB V 9i on Redhat Linux AS
2.1. In this case we are dealing with a rather small number of files
having mostly a large size, some of them are being written
sequentially (redo logs), and some almost constantly (control files).
So the situation seems like an ideal case to use a file system that
best suites to it. Since one can choose the file system type among a
number of these using Linux, I am wondering which one is the more
appropriate or offers the best performance. Besides ext3 there is
reiserfs and xfs and...

Any experience or recommendations?

The most important DB files are located in a (hardware) RAID 10 (5x2
HDs), but I think the file system does not care about that.

Thanks
Rick Denoire

 
 
 

Best file system type for databases

Post by Pep » Sat, 30 Nov 2002 18:57:39



> I am in the process of setting up an Oracle DB V 9i on Redhat Linux AS
> 2.1. In this case we are dealing with a rather small number of files
> having mostly a large size, some of them are being written
> sequentially (redo logs), and some almost constantly (control files).
> So the situation seems like an ideal case to use a file system that
> best suites to it. Since one can choose the file system type among a
> number of these using Linux, I am wondering which one is the more
> appropriate or offers the best performance. Besides ext3 there is
> reiserfs and xfs and...

> Any experience or recommendations?

> The most important DB files are located in a (hardware) RAID 10 (5x2
> HDs), but I think the file system does not care about that.

> Thanks
> Rick Denoire

ext3 or reiser.

Pep.

 
 
 

Best file system type for databases

Post by Steve Holdowa » Sat, 30 Nov 2002 20:44:24


On Fri, 29 Nov 2002 00:25:01 +0100, Rick Denoire


>I am in the process of setting up an Oracle DB V 9i on Redhat Linux AS
>2.1. In this case we are dealing with a rather small number of files
>having mostly a large size, some of them are being written
>sequentially (redo logs), and some almost constantly (control files).
>So the situation seems like an ideal case to use a file system that
>best suites to it. Since one can choose the file system type among a
>number of these using Linux, I am wondering which one is the more
>appropriate or offers the best performance. Besides ext3 there is
>reiserfs and xfs and...

>Any experience or recommendations?

>The most important DB files are located in a (hardware) RAID 10 (5x2
>HDs), but I think the file system does not care about that.

>Thanks
>Rick Denoire

How brave are you feeling? You could always use raw devices. But I
wouldn't recommend it unless you're after ultimate performance.

Personally, I'd use ext2 file systems, but reconfigure them with
biggest blocksize and frag size ( -b 4096 -f 1024 ), cut the reserved
space right down ( -m 1 ), and set the number of inodes right down (
-N <100 times the number of files you expect to store there> ). For
oracle, don't forget that there's bdump and udump dirs that can have a
lot of files if tracing is switched on, so don't go too mad on the
number of inodes 'cos you can't change it later!

I expect that a number of people will suggest ext3 ( is it available
with AS? ), but, although it'll be much faster to recover after a
crash, I don't really have a feel for the performance overhead of the
journalling.

Good luck!

Steve

 
 
 

Best file system type for databases

Post by Centurio » Tue, 03 Dec 2002 07:04:58


"Steve Holdoway" wrote...

> >I am in the process of setting up an Oracle DB V 9i on Redhat Linux AS
> >2.1. In this case we are dealing with a rather small number of files
> >having mostly a large size, some of them are being written
> >sequentially (redo logs), and some almost constantly (control files).
> >So the situation seems like an ideal case to use a file system that
> >best suites to it. Since one can choose the file system type among a
> >number of these using Linux, I am wondering which one is the more
> >appropriate or offers the best performance. Besides ext3 there is
> >reiserfs and xfs and...

**SNIPPED**

Quote:> I expect that a number of people will suggest ext3 ( is it available
> with AS? ), but, although it'll be much faster to recover after a
> crash, I don't really have a feel for the performance overhead of the
> journalling.

> Good luck!

> Steve

But if you are running Oracle with transaction logs (archive logs -
whatever) and store them on a separate volume to the main data, the issue of
recovery after a crash becomes rather academic.  Assuming the worst and the
data files are totally fscked, the journaling isn't going to help much (been
there, seen that - Solaris + UFS) which means restore from tape.  But if you
are doing cold backups....you've lost all your data after the last backup.
Enter archive logs stage right.  Restore from tape, roll on the archive logs
and your up and running basically to the point the disaster occurred.

Make sure your backup scheme handles the archive logs too, and that there is
sufficient redundancy on the volume the archive logs are stored (RAID 0/1 or
RAID 5 - both with a hot-spare).

Cheers,

James