Raw Devices 2006-10-09 - By Alexei_Roudnev
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I think, that your DBA tried to do a bad thing - change disk size on SAN
system and then resize ASM device., It don';t work because Linux don't see
new size if disk is mounted by any way.
You should not
- use ASMLib, it is a piece of garbage.
- don't try to resize disk when ASM device is full.
You should, instead, ADD new disk into the group, when previous one is
filled in (and system will redistribute ASM files), OR add new
ASM disk group and assign new datafile into the tablespace.
OCFSv2 is a controvercial thing - it is fine when it work, buit it adds an
element of instability. I;d better use NFS for backups, but we are runnimng
OCFSv2 in the lab for low-performance file systems (archive logs and
backups) and it works fine (if we have not infrastructure failures).
-- -- Original Message -- --
From: "C'est Pierre" <cestpierre@(protected)>
To: "Fabrizio Magni" <fabrizio.magni@(protected)>
Cc: <suse-oracle@(protected)>; <suse-sles-e@(protected)>
Sent: Monday, October 09, 2006 8:41 AM
Subject: [suse-sles-e] Re: [suse-oracle] Raw Devices
> Hi Fabrizio,
>
> We skipped the option of using ASMLib on this cluster. Our dba said it
> had a limitation (or bug) when a tablespace (or was it raw device?)
> filled up, they couldn't extend the size anymore. This is a migration
> database, so they'll need lots more space than we already have in the
> long run.
>
> We're using RAC and raw devices only, from what he said. An
> alternative in mind is OCFS.
>
> Any thoughts?
>
>
> Thanks,
> Pierre
>
>
> On 10/9/06, Fabrizio Magni <fabrizio.magni@(protected)> wrote:
> > Hi Pierre,
> > just personal curiosity: what's the advantage to have 47 partition on
the
> > same disk?
> > If you are still using the ASM then you can simply use a single
partition
> > (or device).
> > Tablespaces are already divided inside that device optimizing the space
> > usage.
> >
> > Regards
> > Fabrizio
> >
> >
> > On 10/9/06, C'est Pierre <cestpierre@(protected)> wrote:
> > >
> > > Hello all,
> > >
> > > First, I am sys-administrator, not a DBA, so excuse me if I am no
> > > precise with some tech. aspects of Oracle.
> > >
> > > I am in the process of installing a new RAC cluster. Our previous one,
> > > went smoothly, but we used ASMLib, which we aren't using now. Problem:
> > > I created 47 partitions on a scsi disk presented to the server thru a
> > > fibre channel card. These are sda1 thru sda47. However, only the 15
> > > first (except one, which is the extended one - sda4) are usable.
> > >
> > > I wrote the /etc/raw, mapping sda's to raw's just as the dba sugested
> > > for organizational purposes (they aren't sequential, e.g raw51 maps
> > > to sda28).
> > >
> > > I then made this line of bash to create all device nods that weren't
> > > there (and even those that were...just in case):
> > >
> > > for i in `seq -f %g 1 47`; do echo mknod sda$i b 8 $i ; done
> > >
> > > Problem: I can't access past sda16, I get this error:
> > >
> > > dd: opening `/dev/sda16': No such device or address
> > >
> > > when I look at dmesg and /proc/partitions, I only get to see the first
> > > 15 partitions there (or 16, if you count with 'sda')
> > >
> > > sda: sda1 sda2 sda3 sda4 < sda5 sda6 sda7 sda8 sda9 sda10 sda11 sda12
> > > sda13 sda14 sda15 >
> > >
> > > I've googled for this problem and it seems there's a limitation on
> > > scsi disks of 16 partitions per device. Is this true? if so, what is
> > > the solution for this problem? how can I make 47 raw partitions?
> > >
> > > I can still ask our storage administrator to divide this disk into
> > > several disks and then we will group partitions 16 partitions on each,
> > > but this isn't a good solution. Another alternative solution which our
> > > dba presented, was adding ocfs 2 support and make it dance with the
> > > devil by the pale moonlight ;-)
> > >
> > > Let me know your thoughts and especially solutions!!
> > >
> > > Also, your thoughts on ocfs or not as a side note would be apreciated.
> > >
> > > Thank you
> > >
> > > Pierre
> > >
> > > P.S: I'm not french but I love french bread! ;)
> > >
> > > --
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> > > Please see http://www.suse.com/oracle/ before posting
> > >
> > >
> >
> >
>
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