Thanks to alan_at_nabeth.cxo.dec.com and jrodgers_at_linknet.net.
Both responded with the same format as it appeared in my questions, which
made them very easy to read.
Tom Yang email: yang_at_intel1.tdh.qntm.com
Quantum Corporation
SHR1-4/D26
333 South St. phone: (508) 770-2544
Shrewsbury, MA 01545-4112 fax: (508) 770-2869
My questions:
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Hi,
I'm interested in getting the SW300-AA with HSZ40-AF (controller and cache)
for my two identical DEC 3000/700 systems running Digital Unix 3.0.
My questions are:
1. How would I configure the three boxes to achieve highest availability, in
case one of the hosts went down or a disk crashed?
2. What's the advantage of having the HSZ40-AF controller as opposed to, say,
throwing in a couple of expansion shelves with pedestals?
3. Can I put in third party disk drives?
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The answers:
--------------------------------- 1 ------------------------------
alan_at_nabeth.cxo.dec.com wrote:
1. Install V3.2 on the Digital Unix Systems. Run ASE
on the Digital UNIX systems. Get the dual controller
version of the HSZ40 configuration and set it up for
controller failover. If a controller fails, then the
other controller will handle the load. If a system
fails, the other will pick up the load to the extent
possible using ASE.
I don't know if the -AF is a single or dual controller
version.
2. The HSZ40 support RAID-0 and RAID-5 on the controller
as well as the battery backup write-back cache. The
limitation is that you have all the I/O going through
a single host adapter. For pure performacde multiple
host adapters will nearly always beat a single adapter.
There are two versions of the HSZ40 module available;
the "Classic" which I think is the -Ax version and the
newer -Bx versions. The -Bx versions run HSOF V2.5
which supports controller based mirroring in addition
to Stripping and RAID-5. I think qualification of the
Classic with V2.5 is still going on.
Another advantage of an HSZ40 is connectivity. Using
bare devices on a Fast/Wide/Differential SCSI controller
Digital UNIX is currently limited to 7 devices. Using an
HSZ40 you can have 32 logical devices, which maybe
single disks or arrays. If you need the best possible
performance out of 24 drives, then get a bunch of host
adapters and spread the drives among them, then use
LSM to get striping and mirroring. Throw in Prestoserve
to help the file system write preformance.
If an HSZ40 provides "good enough" performance on a single
host adapter, then take advantage of the features that it
offers.
3. Not and have a supported configuration. Random 3rd party
drives may appear to work, but since they haven't been
qualified, there's no guarantee that they'll work. Quoting
the applicable section of the SPD:
"Digital will not assure correct opreation of any
unqualifies device, nor assure that such devices
will not have impact on other supported devieces,
on the controller itself, or on a Digital system
configuration".
--------------------------------- 2 ------------------------------
jrodgers_at_linknet.net wrote:
Hello, Tom I am Jimmie Rodgers with Intenational Computer Systems a
Direct Solutions provider for Digital Equipment Corp. I read your
e-mail and determined that your questions are very valid and can be
answered as follows.
1. Your question about how to configure three storage boxes to
achieve highest availability. Funny you should ask, I just
completed an installation, which required 4 external storage cabinets
connected with a cluster. The storage arrangement was connected to a
cluster of 2100's. We achieved fault tollerance with an application
by Digital, called LSF (Load Sharing Facility) and PVM. These
applications are prevalent with parallel processing systems to
balance routing of code to be processed to large numbers of
individual workstations in a farm configuration. These applications
in conjuncition with redundant HSZ40-AF controllers and power
supplies will give you the best redundancy and data protection
possible.
2. Your answer to advantages of HSZ40-AF controllers as opposed to
just expansion shelves and pedestals is yet another good question. I
and this is my opinion believe the HSZ40-AF is the controller of the
future here today. With the available cache options and stability
for the price it is excellent. The all in cabinet system of the
SW300-AA offers you very good storage with excellent redundancy and
ease of upgrading and maintenance.
3. Yes you can put 3rd party drives within the storage works system.
You need to make sure that if you decide to use Seagate Barracuda
drives that you use the BA350 enclosure that has the dual fans. This
will prevent overheating, since the Barracuda 4.3GB and 9.0GB drives
spin in excess of 7200rpm's
If you have any other questions please, e-mail your questions or
comments. I will also be happy to help you with any other
configurations you may have about network integration or any of the
new systems out by Digital. I hope I have answered any questions you
may have had about the Cabinet.
Jimmie,
Received on Fri Jun 09 1995 - 21:24:19 NZST