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Re: backup qualifiers

 
Wim Van den Wyngaert
Honored Contributor

Re: backup qualifiers

On a server in use, I got a 5 to 10% gain in wall time when I did set file/cac=no for the source file and the destination directory. The file was only 300 MB and extended file cache was in use.

FTP between 2 cluster nodes arrived at about half the speed.

Wim
Wim
Ian Miller.
Honored Contributor

Re: backup qualifiers

Its curious that disabling caching for the file affects the result if BACKUP bypasses XFC.

Current recommended values for process quotas for running backup are lower than previously recommended.
____________________
Purely Personal Opinion
Wim Van den Wyngaert
Honored Contributor

Re: backup qualifiers

Ian,

Found this on the subject of 7.2-1

BACKUP uses the XFC cache. This can impact the performance of other applications that use the XFC cache. This change keeps BACKUP from monopolizing the XFC cache.

So, it depends on which patches are installed ??? And is it completely disabled ?

I tested it on 7.3 with XFC 2.0 installed but not 3.0 or higher. I did each test 2 times and got 5 and 10% better performance.

Wim

Wim
Wim Van den Wyngaert
Honored Contributor

Re: backup qualifiers

Note that I did the test on a mchine with VCC_FLAGS on 1, thus not XFC but VCC was active.

Wim
Wim
Marc Van den Broeck
Trusted Contributor

Re: backup qualifiers

Wim,

I have VCC_FLAGS also on 1. This are my vcc parameters:
VCC_FLAGS 1
VCC_MAXSIZE 100000
VCC_MAX_CACHE -1
VCC_MAX_IO_SIZE 127
VCC_MAX_LOCKS -1
VCC_READAHEAD 1
VCC_WRITEBEHIND 1
VCC_WRITE_DELAY 30

Marc
Wim Van den Wyngaert
Honored Contributor

Re: backup qualifiers

I did a test and looked at show mem/cac.

With XFC enabled in 8.2, no reads bypassed the cache. All writes bypassed the cache.

With XFC in VIOC mode (7.3 XFC 2.0), the result was the same.

Wim
Wim
Marc Van den Broeck
Trusted Contributor

Re: backup qualifiers

thx all for info

Rgds
Marc