[DRBD-user] IBM Server Machines with DRBD-0.7.x

Paul Bennett paul-bennett at nc.rr.com
Thu Mar 31 05:29:13 CEST 2005

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On Wed, 30 Mar 2005 21:40:25 -0500, Linux GNUbie <gnubie at gmail.com> wrote:

> On Tue, 2005-03-29 at 21:16 -0500, Paul Bennett wrote:
>> Do you plan on massive future scalability? A full Bladecenter will give
>> you marginally more CPUs per U of space than (I think) any ordinary
>> xSeries. If you're buying lots of gigahertz, that will be a big factor.
>> Using Bladecenter bays for SCSI storage is going to cut into that.

> Not necessarily for scalability but for a practical hardware of choice
> for servers intended for DHCP, NFS, OpenLDAP and DNS.  Maybe for the NFS
> server, the SCSI HDD should be scalable for the file servers.

There are so many things that the word "best" can mean. Have you looked at  
the Configuration & Options Guide? Last time I saw it, there was a lot of  
good information in the beginning for the target market of each server.

It's at http://www.ibm.com/servers/eserver/xseries/library/configtools.html

It looks like the x345 has been withdrawn in favor of the 346, too. You  
may be able to get the x345 from business partners or resellers, but not  
directly from IBM.

> You mean, the blades are not that good hardware of choice when it comes
> to hardware stability?

I can't speak for their stability in real terms. What I can say is that  
they're really designed to be replaced on a whole-machine basis (and then  
repaired and sold as pre-owned) as opposed to ordinary xSeries which are  
designed to be replaced part-by-part. If you own (say) 500 Blades, it can  
be a huge economic advantage.

>> OTOH, I've been inside the x345, and it's a pleasure to expand and to  
>> work
>> on.
> I was once able to work with IBM xSeries 345 and it was so cool and
> stable.

The whole xSeries range are great to work with. I can't recommend them  
highly enough.

> The initial plan is to purchase 4 or 6 server machines for the said
> services and it will be 2 or 3 pairs of those machines will be
> configured with Heartbeat and DRBD.

Hm. A Bladecenter holds 14 blades. Depending on your needs, that's only 6  
slots used on CPU, but you're only allowed one SCSI expansion unit per CPU  
blade, for a total of 12 SCSI hard drives.

Six x346s will be 12U of rack space (instead of 7) but will support 36  
SCSI hard drives (instead of 12).

For NFS, I'd say the choice of x346 is clear, with each unit capable of  
880GB instead of the 290GB max for a SCSI Blade. If you've got 12U  
available, I say go for it. Also, you might want to recommend using x336s  
for the non-NFS servers, where storage is less of an issue. You'll save  
money, power and space.


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