Data Cache on a Power Challenge XL

Data Cache on a Power Challenge XL

Post by Kenneth Marti » Fri, 15 Dec 1995 04:00:00



Hello,

I am trying to figure out where NFS data is cached on the Power Challenge
XL.  When we cat a 121 MB file from an NFS server to /dev/null, the first
time takes 2 minutes 46 seconds.  The second time takes 3 seconds.

Doing the same experiment on a Power Indigo 2, the first time takes 2
minutes 40 seconds.  The second time takes 3 minutes 31 seconds.

This would indicate that the NFS data is being cached somewhere on the
Challenge and that all 121 MB is cached and it doesn't seem to be the NFS
server since 3 seconds is much too fast for the network and the Indigo
showed no performance gain the second time.

My questions are is this cached in main memory?  How is the upper limit
of this cache determined (files larger than 128 MB don't seem to get
cached like this)?  Would throwing in more RAM allow for a larger
cache?

We do searches on huge databases on this machine all day, and caching
these databases would give a huge benefit in performance.

Ken Martig
ZymoGenetics, Inc.

 
 
 

Data Cache on a Power Challenge XL

Post by Adam Sween » Fri, 15 Dec 1995 04:00:00


Irix uses the free memory in your system as a file data cache.
The more memory you have, the more file data it will cache.
This file data cache is used by all of the Irix file systems,
including NFS.

Adam Sweeney



>Hello,

>I am trying to figure out where NFS data is cached on the Power Challenge
>XL.  When we cat a 121 MB file from an NFS server to /dev/null, the first
>time takes 2 minutes 46 seconds.  The second time takes 3 seconds.

>Doing the same experiment on a Power Indigo 2, the first time takes 2
>minutes 40 seconds.  The second time takes 3 minutes 31 seconds.

>This would indicate that the NFS data is being cached somewhere on the
>Challenge and that all 121 MB is cached and it doesn't seem to be the NFS
>server since 3 seconds is much too fast for the network and the Indigo
>showed no performance gain the second time.

>My questions are is this cached in main memory?  How is the upper limit
>of this cache determined (files larger than 128 MB don't seem to get
>cached like this)?  Would throwing in more RAM allow for a larger
>cache?

>We do searches on huge databases on this machine all day, and caching
>these databases would give a huge benefit in performance.

>Ken Martig
>ZymoGenetics, Inc.



 
 
 

Data Cache on a Power Challenge XL

Post by Adam Sween » Sat, 16 Dec 1995 04:00:00





>>   Irix uses the free memory in your system as a file data cache.
>>   The more memory you have, the more file data it will cache.
>>   This file data cache is used by all of the Irix file systems,
>>   including NFS.

>I think you misunderstood Kenneth's problem: I understand that
>both the Challenge as well as the Indigo^2 are NFS *clients* to
>an third NFS server. And I think that IRIX will *not* do caching
>for (remote) NFS data. (That's why he said '3 seconds is much too fast
>for the network')

Excuse me, but I'm the guy who works on the Irix file cache.  I
think I know how it works.  We certainly do cache file data for
remote NFS files in the client system's file cache.  That's
why it's not going over the network the second time around when
he has enough memory to cache the entire file on the client.

Adam Sweeney

 
 
 

Data Cache on a Power Challenge XL

Post by Andres Kru » Sat, 16 Dec 1995 04:00:00



>   Irix uses the free memory in your system as a file data cache.
>   The more memory you have, the more file data it will cache.
>   This file data cache is used by all of the Irix file systems,
>   including NFS.

I think you misunderstood Kenneth's problem: I understand that
both the Challenge as well as the Indigo^2 are NFS *clients* to
an third NFS server. And I think that IRIX will *not* do caching
for (remote) NFS data. (That's why he said '3 seconds is much too fast
for the network')

But Kenneth: Maybe your Challenge has CacheFS installed for the
filesystem you've mounted from that NFS server?
That would allow the NFS files to be cached locally on a disk on the
challenge. Then of course the challenge file system cache comes
into action, allowing a cache of the entire file.

But watch out, there is some danger to using CacheFS for NFS
filesystems that contain data that changes a lot. You might get
into a situation where you cache contains inconsistent data.

But maybe I misunderstood...

Cheers,

      Andres

>   Adam Sweeney



>   >Hello,
>   >I am trying to figure out where NFS data is cached on the Power Challenge
>   >XL.  When we cat a 121 MB file from an NFS server to /dev/null, the first
>   >time takes 2 minutes 46 seconds.  The second time takes 3 seconds.
>   >Doing the same experiment on a Power Indigo 2, the first time takes 2
>   >minutes 40 seconds.  The second time takes 3 minutes 31 seconds.
>   >This would indicate that the NFS data is being cached somewhere on the
>   >Challenge and that all 121 MB is cached and it doesn't seem to be the NFS
>   >server since 3 seconds is much too fast for the network and the Indigo
>   >showed no performance gain the second time.
>   >My questions are is this cached in main memory?  How is the upper limit
>   >of this cache determined (files larger than 128 MB don't seem to get
>   >cached like this)?  Would throwing in more RAM allow for a larger
>   >cache?
>   >We do searches on huge databases on this machine all day, and caching
>   >these databases would give a huge benefit in performance.
>   >Ken Martig
>   >ZymoGenetics, Inc.


--
-----------------------------------------------------------------------
Andres Kruse      | NIKHEF - National Institute for Nuclear Physics

-----------------------------------------------------------------------
 
 
 

1. FS: (2) Power Challenge XL's and (1) Power Challenge L

Here are the configs, the one Challenge XL boots up fine, the other gives a
poke error, The Challenge L is untested but has a bad power supply.  Will
sell all three together for $1,500.00 or best offer. Both Power challenge
XL's are in fairly good shape cosmetically, the Challenge L is missing the
front panel.

SGI Power Challenge XL
(1) 030-0604-004
(1) 030-6613-106/B
(2) 030-0625-112
(1) 030-0536-003 REV D
(1) 030-0522-007
(1) SLAG2 030-0788-001
(1) ACCA-0152-2002    FORE Fiber Optic Card
(2) removeable drives
(2) FDDIXPress Mezzanine board Ports
(2) working power supplies
Boots up fine.
genlock port
stereoview
Monitor port

SGI Power Challenge XL
(1)030-0613-006
(1)030-0614-006-A
(4) 030-0625-112
(1) 030-0646-104(A)
(1) 030-0242-006
(1) 030-0522-007
(1) ACCA-0152-2002    FORE Fiber Optic Card
(4) removeable drives  (but boot drive was stolen, so used drive for other
machine for testing)
(1) other board with all the SCSI connections
(1) FDDIXPress Mezzanine board Port
(2) working power supplies
Gives a POKE error, but comes up otherwise.

SGI Challenge L
(1)030-0604-006 REV D
(1)030-249-013
(1)030-0604-0613 REV C
(1)030-0527-508
(1) ACCA-0152-2002    FORE Fiber Optic Card
(1) removeable drives
(1) other board with all the SCSI connections
(2) FDDIXPress Mezzanine boards
(1) bad power supply


2. removing !new icon?

3. Need power in LA to power up a Challenge XL

4. New PC Security WEb page !!!

5. FS POWER CHALLENGE XL network server

6. Printcap for LX-800 EPSON

7. Mysterious blue box in my Power Challenge XL - Thank you all very much!!!

8. Users not added to Exchange when using SBS console

9. Onyx/Challenge rack/XL power boards

10. FS SGI Power Challenge XL ebay $840 today

11. [Fwd: memory interleaving power challenge XL]

12. memory interleaving power challenge XL

13. FS: Power Challenge XL