| Title: | + OpenVMS Clusters - The best clusters in the world! + |
| Notice: | This conference is COMPANY CONFIDENTIAL. See #1.3 |
| Moderator: | PROXY::MOORE |
| Created: | Fri Aug 26 1988 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 5320 |
| Total number of notes: | 23384 |
HI,
One of our big customers in Hong Kong has a very aggrestive test plan
in mind and they really want to test out the new Memory Channel and VLM
feature and Oracle Parallel Server configuration asap. The current
configuration for this customer is there are two separate computer
rooms located in two different buildings. There are two AlphaServer
8400 5/300 systems with 2 CPUs and 1GB of memory and a lot of RZ disks
to form the CI Cluseter located in each computer room. These two CI
clusters are being connected through the FDDI ring to form another
FDDI Cluster. The system configuation will be shown as follow:
===================================================
+ FDDI Cluster +
===================================================
| Computer Room 1 | Computer RM 2
| (Building 1) | (Building 2)
Concentator Concentator
| | | |
| | | |
8400 8400 8400 8400
\=====/ \=====/
\MC / \MC /
* *
/ \ / \
disks...disks disks..disks
^ ^
| |
+-----------------------------+
Remote Volume Shadows Sets (Part of the disks)
Assuming that all the 8400s is running OVMS V7.1 and OVMS Cluster V7.1
which support Memory channel and VLM. In the meantime, Oracle V7.3.2.3.3
which will support Memory Channel and VLM option and the OPS have also
been installed. (We will work with Oracle for this test.)
Before to start the real test based on the above system configuration and
software, there are few questions that we want to clarify:
Q1: Is that a workable configuration based on each of the local 8400s
formed the CI cluster with memory channel interconnect and then form
the FDDI cluster and part of the disks will be formed the remote
volume shadows sets?
Q2: What will be the performance gain when the Memory channe interconnent
has been used comparing without the Memory Channel?
Q3: Is there a way to use Memory Channel Interconnect to connect the
two CI clusters in two separate computer rooms? (As I understand,
there is the cable limitation for the Memory Channel which is only
around 10 feet long.)
Q4: Are there any performance issues if we want to set up the Oracle
Parallel Server environment under this FDDI Cluster? On the other
hand, can we run the OPS under this configuration and still obtain
good performance and high availability?
Q5: Can we enable the VLM feature under the FDDI Cluster configuration?
If yes, what will be the performance gain? Any suggestions?
Q6: How well the system (or OPS) can handle the data integrity during
one of the system crash and the VLM option has been enabled under
this FDDI cluster?
Q7: Are there any performance figures available for this kind of
system configuration? The customer has some concerns on the
performance under this configuration. The customer wants to have
high availability and fast response (good performance) production
environment.
Q8: Are there any reference sites which have the similar configuration
setup?
Q9: Are there any other technical issues needed to be considered to
setup such configuration?
Thanks for any suggestions.
Edmond
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 5258.1 | ALEPPO::mse_notbuk.mse.tay.dec.com::bowker | Mon Mar 17 1997 13:49 | 3 | ||
See CHEFS::MDF (Business Recovery Server [BRS] Note Conference) | |||||
| 5258.2 | some answers and some more questions | STAR::CROLL | Tue Mar 18 1997 11:36 | 68 | |
I'm a bit confused by your diagram. Does this picture
| |
| |
8400 8400
\=====/
\MC /
*
/ \
disks...disks
mean that you have both a memory channel and a CI? Or do you intend to replace
CI with memory channel? The latter won't work, since there's no way to connect
disks directly to memory channel. I'm going to assume you have both memory
channel and CI in each half.
> Q1: Is that a workable configuration based on each of the local 8400s
> formed the CI cluster with memory channel interconnect and then form
> the FDDI cluster and part of the disks will be formed the remote
> volume shadows sets?
Yes, this configuration is a legal cluster. Please note that it is one cluster,
not separate CI clusters and FDDI clusters.
> Q2: What will be the performance gain when the Memory channe interconnent
> has been used comparing without the Memory Channel?
The performance gain will come by moving all non-disk-I/O traffic off the CI to
the memory channel. This will give you back some disk I/O capacity on the CI,
and give you more locking and other cluster traffic capacity on the memory
channel. Unfortunately, I don't have any numbers handy, so I can't say how much
of a gain you'll see.
> Q3: Is there a way to use Memory Channel Interconnect to connect the
> two CI clusters in two separate computer rooms? (As I understand,
> there is the cable limitation for the Memory Channel which is only
> around 10 feet long.)
No; the memory channel cable limit is about 10 feet or so. It's a short
interconnect.
> Q5: Can we enable the VLM feature under the FDDI Cluster configuration?
> If yes, what will be the performance gain? Any suggestions?
VLM is a feature of the operating system, and of Oracle. It's always there in
the operating system, regardless of whether you're in a cluster or not. Your
application either uses it or not. It's impossible to quantify how your
performance will change using VLM without a lot more information about the
application.
> Q6: How well the system (or OPS) can handle the data integrity during
> one of the system crash and the VLM option has been enabled under
> this FDDI cluster?
Assuming you've set up your shadow sets and related stuff correctly, OpenVMS
will correctly recover from system crashes and you won't lose data. I don't
know enough about Oracle Parallel Server to know how it deals with recovery, but
I assume there are safeguards built in to handle these cases. Folks in the MDF
conference, or in VMSNOTES, may know more.
John
| |||||
| 5258.3 | Your assumption is correct | HGOVC::EDMONDLEUNG | Tue Mar 18 1997 12:33 | 15 | |
RE: .2
HI John,
Your assumption is correct. There have both memory channel and CI in
each half.
For Q1, I am not too sure I understand that what you mean about there
is only one cluster. Do you mean there is only one cluster from the end
user prespecitve since both of the CI clusters have been clustered by
another FDDI clusrter. Therefore, there is only one cluster in that sense.
Is that correct?
Thanks for your suggestions
Edmond
| |||||
| 5258.4 | EVMS::MORONEY | Tue Mar 18 1997 13:17 | 26 | ||
> For Q1, I am not too sure I understand that what you mean about there > is only one cluster. Do you mean there is only one cluster from the end > user prespecitve since both of the CI clusters have been clustered by > another FDDI clusrter. Therefore, there is only one cluster in that sense. > Is that correct? There is no concept of subclusters in OpenVMS Clusters. In fact it deliberately avoids them. When you say "since both of the CI clusters have been clustered by another FDDI cluster" you misuse the term. The correct way to state it is "the CI nodes have been connected by FDDI, forming a single cluster rather than two smaller clusters." The clustering software considers all connections to be equal, other than the speed when there are multiple connections between two nodes. (in your examples the 8400s in one building have 3 connections between them, memory channel, FDDI and CI. The MC is the fastest and will be used between them. An 8400 in one building has only one connection to either 8400 in the other building (the FDDI) so the FDDI will be used in the communication between them.) If you don't enable clustering over the FDDI you'll get two separate clusters that can communicate only by DECnet, TCP/IP etc. Do you want one or two separate clusters? Since you show shadowsets on both sides of the FDDI you apparently want one single cluster. -Mike | |||||