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!
! Note:
! The LAD disk block cache is structured as a number of fixed-size
! buckets. You must specify both the bucket size and the number of
! buckets for the cache.
!
! The LAD cache is allocated from non-paged pool and is in no way
! associated with the XFC cache. The total LAD cache size in bytes
! may be determined by the formula:
!
! cache-bytes = bucket-size-in-blocks * number-of-buckets * 512
!
! Be sure the SYSGEN parameters NPAGDYN/NPAGEVIR are sized appropriately.
!
! The following keywords with values are accepted by this procedure:
!
! BUFFER_SIZE - A number between 3 and 8 denoting the
! bucket size in blocks as follows:
! 3 - 8 blocks
! 4 - 16 blocks
! 5 - 32 blocks
! 6 - 64 blocks
! 7 - 128 blocks
! 8 - 256 blocks
! CACHE_BUCKETS - Number of buckets
! MAXIMUM_SERVICES - Maximum number of services (max=1024)
! WRITE_LIMIT - Server wide count of asynchronous writes
!--
BUFFER_SIZE = 3 ! default (8 block buckets)
CACHE_BUCKETS = 512 ! Default setting
WRITE_LIMIT = 0 ! No async writes
MAXIMUM_SERVICES = 256 ! default (typically more than enough)
The following table provides a short description of each of the parameters:
DescriptionParameter
The InfoServer block cache is structured as an array of fixed-size buffers (also called
buckets). The BUFFER_SIZE parameter determines the size of each buffer or bucket.
The numeric value of this parameter is an integer in the range 3 through 8,
representing the bucket size in 512-byte blocks as follows. Bucket sizes larger than
32 blocks might not be appropriate for most users. The OpenVMS client segments
I/O requests larger than 31 blocks into 31-block chunks, which could result in
excessive I/O activity to the disk. The cache is allocated from nonpaged pool and
is dedicated solely to the LAD driver.
BUFFER_SIZE
8 blocks (default)3
16 blocks4
32 blocks5
64 blocks6
128 blocks7
256 blocks8
Determines the number of buckets in the cache. The default is 512. Numbers larger
than 16384 might adversely affect performance. To reach a desirable cache size,
consider increasing the BUFFER_SIZE parameter.
CACHE_BUCKETS
Sets the maximum number of services that can be defined at one time for the server.
The value of this parameter must be a power of 2. The default and minimum value
is 256 (adequate for most circumstances); the maximum value is 1024. Each service
descriptor consumes nonpaged pool; however, unused services consume 4 bytes
each.
MAXIMUM_SERVICES
The number of asynchronous write operations that can be outstanding for the
server at any time. The default is 0 (no outstanding asynchronous write operations).
WRITE_LIMIT
C.3 Setting Up the InfoServer Server 233