| The customers expectations are correct in the disks whould swap
until the I/O is completed for all disks. I remember problems
similar to this in the past but no specific product changes have
been made, I will try to refresh my memory. For now, I recommend
the following:
o Use SYS$MANAGER:PERCEPTICS$VERSIONS.COM to generate a list of
the LaserStar component ids and please post. V3.3 has a few
variant releases.
o What is the optical hardware, related I/O interface, and host
processor. Is this part of a cluster? If so, are the disks
mounted /CLUSTER?
o Try changing the MINSWAP and/or IORATE values. Extract from help
below:
JBUTIL
SET PARAMETER /MINSWAP=time
MINSWAP is the amount of "time", in seconds, that a disk
cartridge will remain in a drive before it can be removed as
part of a swap operation. The MINSWAP interval begins after the
disk has been inserted and spun up.
Once a disk has been inserted into a drive in the jukebox, it
will remain in the drive until the MINSWAP interval has expired,
regardless of the amount of activity on the disk or the number of
other disks waiting for a drive. The minimum value for MINSWAP is
5 seconds.
JBUTIL
SET PARAMETER /IORATE=seed
IORATE is the name used for a seed value used in the jukebox swap
algorithm. Large IORATE seed values will help cause heavily used
disks to remain in a drive longer than their MINSWAP interval.
The IORATE "seed" value is fed into an equation whose result is
used to determine if the time the disk will be allowed to remain
in the drive will be extended. The larger the IORATE "seed"
value the less likely a disk performing servicing many I/O's
will be swapped. Very large IORATE values will not significantly
increase the amount of time a disk remains in a drive due to the
exponential nature of the equation.
Setting IORATE to zero will disable this feature completely so
that only the MINSWAP time controls swap eligibility.
swap_equation
The number of seconds for a volume to become eligible to be swap
is a function of MINSWAP, IORATE and the number of I/O operations
the volume has performed since it has been placed in the drive.
The following equation computes an operation rate, which is one
of the values used to determine swap eligibility.
OPS_RATE = IORATE * OPS / SEC_IN_DRIVE / SEC_IN_DRIVE
where:
OPS_RATE = operation rate of the volume
IORATE = value of the IORATE parameter
OPS = total number of operations since the volume was moved
into the drive
SEC_IN_DRIVE = number of seconds since the volume was moved
into the drive
The volume will be eligible for swapping when it has been in a
drive longer than MINSWAP seconds and the OPS_RATE value is zero.
The IORATE Impact on Swap Time Eligibility indicates some example
showing how long a volume will remain in a drive based on IORATE
and the number of operations per second. MINSWAP is set to five
sconds for these examples.
Table 1-1 IORATE Impact on Swap Time Eligibility
Operations
per
IORATE Second Eligibility second
1 5 6
2 5 11
3 5 16
4 5 21
1 10 11
2 10 21
3 10 31
4 10 41
Any 0 5
value
As another example, if IORATE=2 and the volume gets 500
operations in the first second and is then idle, the swap will
not occur until 32 seconds have elapsed. The OPS_RATE will not
be greater than zero until SEC_IN_DRIVE equals 32.
Also if the OPS value exceeds 1024 the volume will be allowed to
swap when MINSWAP seconds has been exceeded. This puts an upper
limit on fast drives from preventing other volumes use of the
drive.
Rob
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