| Title: | HSZ40 Product Conference |
| Moderator: | SSDEVO::EDMONDS |
| Created: | Mon Apr 11 1994 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 902 |
| Total number of notes: | 3319 |
Hi,
Can anyone explain in details how the switch MAXIMUM_CACHED_TRANSFER
works? I saw many topics about that but no one conclusive or clarify.
We know that we can set from 0 to 1024 (blocks). Default is 32
(blocks). How to set this :
01 HSZ50
01 cache 64MB
WBC enabled
3 striped mirrorsets :
stripe1 = mirror1+mirror2 = mirror1 ( rz29b + rz29b) + mirror 2 (rz29b
+ rz29b)
strip1=stripe2=stripe3
Total 12 disks - 3 storagesets : D100 , D200 e D300 - 8GB each.
What is a good settings for MAXIMUM_CACHED_TRANSFER?
It's OPENVMS + INGRES. Customer says that READ of big tables is the
question.
Thanks.
Leandro.
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 771.1 | Match it to the Average Transfer size | KERNEL::LOANE | Comfortably numb!! | Wed Feb 19 1997 14:18 | 11 |
> Can anyone explain in details how the switch MAXIMUM_CACHED_TRANSFER
> works? I saw many topics about that but no one conclusive or clarify.
This parameter is used to stop (for example) a large I/O from
removing useful data from the cache; any I/O larger than this
parameter will NOT use cache. Before you play with the parameter,
it's useful to know what the I/O workload on the drives is; find
out the Average I/O Transfer size from DECPS or stare at the DEVICE
DISPLAY in VTDPY for as long as you can stand it....this should
give you an idea of whether the default 32 is too low (on a device
by device basis). The performance boost CAN be dramatic.
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| 771.2 | I will try...Tks. | VAXRIO::LEANDRO | Thu Feb 20 1997 08:08 | 4 | |
Thanks.
Leandro.
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