backup qualifiers

[Wim Van den Wyngaert]

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

[Ian Miller.]

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.

[Wim Van den Wyngaert]

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 Van den Wyngaert]

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

Wim

[Marc Van den Broeck]

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]

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

[Marc Van den Broeck]

thx all for info

Rgds
Marc