Hi,
We are just puting together an Alphaserver 1000A setup, and I have a
few questions:
1. We are seriously considering a RAID 3-port controller using level-5
technology (striping+parity). Question: we would like to 'recycle' some of
the 9G, narrow fast-scsi drives that we have (both Segate and
Micropolis). Has anyone tried it? Dec said that they were not
'supported', but they did not say that it does not work (i.e.
they don't know). I was told that Dec might go in the direction of
9G drives eventually so the idea is not totally hopeless.
2. Assuming I can do this, will a Prestoserve card provide a *significant*
boost (e.g. in NFS performance)? I'm not sure since Prestoserve seems to
be doing write behind cache, which is already in the RAID controller
card (which will have 32M of memory). The OS also has some cache mechanism.
I understand that the NVRAM is faster than traditional memory, but I'm
not convinced that this will boost anything significant. The few M of
cache that I get this way, does not seem to be too large (compared to
the ~50G that we are planning to have on-line). Or am I missing
something here?
3. Is it possible to use 2 network cards to do a 'striping' like config?
I have two etherswitch ports for the cards, and the backplane of the
etherswitch is fast enough. I know I can have 2 IP addresses and
manually split the clients between the cards. Can I do it automatically
(i.e. both cards have the same IP address, and the kernel figures
out which one to use)? All this with 10baseT (UTP). [Eventually I will go
up to 100BASET (few month time scale)]. Dec said no way. I saw this done
once on a Sun.
4. What is the story with the extra 4 PCI slots? I found in the archive that
the RAID controllers should go into the first 3 slots (before the
PCI bridge). Is the same true for the fast ethernet card? What about
the prestoserve? If all should be before the bridge chip (Digital Systems
and Options Catalog implies this), just what can I do with the extra 4
slots? Eventually I might have to put in an extra SCSI card for slow,
narrow, non-disk devices. Can it go there (after the bridge)? Can I put
an accelerated graphics card there?
5. I'm a little bit confused with memory options. As I understand, I have
4 banks, and each can take ...64, 128, 256M of memory. The total is
512M. Well, 4x256M is 1G, not 512M. Why? Since edu. price for 128M
Kingston is like $5000, I'm tempted to fill the box with these kits,
reaching nearly 512M (448M, actually). Loosing 64M capacity is not
a big deal, but loosing a possible 512M is a difference. What is the story
here? Is the 512M total a hard limit, or it's a relics from past when
128M was the largest option (32M SIMM's).
6. Is it possible to mix narrow and wide SCSI devices? As I understood,
the bus can handle both, but one has to be carefull with the cables.
I would like to put some external narrow devices on the on-board wide
SCSI bus without killing the internal wide disks. Just to add a bit more
of confusion: If I add a quad speed internal CD-ROM (which I think is
narrow), can I put an external wide disk on the same bus?
7. Just a stupid one: is this quad-speed drive (RRD35) 'multisession' capable?
It is MS with the Photo-CD format, but what about ISO9660+RockRidge?
Thanks,
Gyula
Received on Thu Mar 07 1996 - 23:26:30 NZDT