R: R: Questions
Wed, 3 Nov 1999 02:58:19 +0100
> > > You might want to take a good look at drive warranties and MTBF
> > Well, this shouldn't matter too much as long as a virtual 4-disks raid
> > is concerned.
> Ok, but then you can also buy the SCSI drives, don't you think?
For the cost of 2 SCSI drive + 4 SCSI interfaces, you can easily afford 4 EIDE
drives of equal capacity (the EIDE interface costs nothing, since it is already
built on whatever motherboard you get). And this way you get two systems which
are more independent each other, too.
You could argue that one could build two systems each with a SCSI disk and a
single SCSI drive to reduce costs, than use NBD or wathever else to mirror the
disks. You're probably right, but I believe that the choice of 2 EIDE disks per
system would increase the performance as well as the availability of each
If a disk crashes, with the (1 SCSI disk + 1 SCSI interface)/server solution
the whole server crashes since even the root fs reside on the crashed disk.
With the 2 EIDE disks/server solution, one can configure Linux to start
mirroring at the boot, thereby letting more chances also to the server having
the crashed disk to start.
This is really not an issue, however. Unless you are going to do also a bit of
However, if a server crashes I fell much more confortable with 2 mirrored disks
on the remaining server.
> > >> - Focusing development efforts more on less on the
> > >> typical Linux hardware, which is around EIDE storage.
> > >
> > > There isn't really any difference for the shared-nothing case.
> > But actually Linux/HA doesn't provide disk mirroring through network in any
> > way, right? The project is focused on high-end hardware...
> Absolutely no. The HOWTO was talking about it, but the project is
> actually open to any architecture. In fact, we have explicitly not opted
> for high end hardware, so we get a broader tester base.
Thank you again, Volker.
Giampaolo Tomassoni Information Systems Consultant
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