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Chapter 3 Operations after Installation
This chapter describes operations required after installing.
3.1
Set up system with large amount of memory
CPU time is extensively occupied by fsflush daemon.
fsflush daemon finds modified data and metadata, which have not been written into backing store, then
writes the data into backing store.
Therefore on a system with large amount of memory, fsflush takes a long time to examine the whole of the
memory, which may result in occupying a certain cpu for a long time.
By changing the following kernel parameters, you can adjust the timing of launching fsflush daemon and
size of memory scanned per launch.
tune_t_fsflushr
autoup
If tune_t_fsflushr is too large, then amount of memory fsflush examines at a time will be large, too. So the
default value is recommended.
In the case of a system with more than 32 Gbytes of memory, fsflush might not be able to examine all
memory within 30 seconds, which is the default value of autoup. If fsflush cannot examine memory within
30 seconds, fsflush does not run periodically and it affects the system.
You may observe by the mpstat(1M) commad that the system time of a certain cpu is nearly 100%.
In such a case, you should change the value of autoup according to amount of memory of the system. The
recommended values are as Table 3.1. "amount of memory" means the amount of memory installed to each
domain on a system with multiple domains.
Specifies the interval by seconcd at which fsflush daeamon is launched. The default is
1.
Specifies the time by second at which fsflush daemon scans whole memory.
Increasing the value of autoup keeps the buffers around for a longer time in memory.
The default is 30.
5
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