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Conference decwet::advfs_support

Title:	AdvFS Support/Info/Questions Notefile
Notice:	note 187 is Freq Asked Questions;note 7 is support policy
Moderator:	DECWET::DADDAMIO

Created:	Wed Jun 02 1993
Last Modified:	Fri Jun 06 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	1077
Total number of notes:	4417

1060.0. "log file size" by MLNCSC::VOCI () Thu May 15 1997 08:57

    Hello,
    
    on Digital Unix 4.0b how can I increase the size of the log file?
    
    Thanks,
    Gea

T.R	Title	User	Personal Name	Date	Lines
1060.1		DECWET::MARTIN		`Thu May 15 1997 12:08`	20
	First, why do you want to? According to the tests we've done, a log smaller than 4 megabytes reduces performance, and a log larger than 4 megabytes also reduces performance. If you're running into the "log half full" problem, I think that's been resolved. Let me know and I'll check with the engineer who's been working on it. And finally, the answer is: Use the undocumented '-l' flag with mkfdmn to specify how many 8K pages should be in the log. Default is 512 pages, which equals 4 megabytes. If you specify a number of pages not divisible by 4, you'll get 512 pages. You're also constrained to use a minimum of 512 pages, and a maximum of 65532 pages. To my knowledge, you cannot change the size of the log in an already existing domain. All of this information should be considered DIGITAL Internal Use Only, as I have no idea how much is fit for public consumption. --Ken
1060.2	switchlog -l	DECWET::BRADY		`Thu May 15 1997 15:55`	5
	You can also use /sbin/advfs/switchlog with the undocumented -l flag (same usage as with mkfdmn) to move the log on a multi-volume domain AND resize it in one step. Mike B.
1060.3	re: .1	NNTPD::"[email protected]"	Mark Angel	`Fri May 16 1997 09:08`	5
	What is the fix to the "log half full" problem. I've had 3 systems running V4.0B panic with that error and always while running defragment. I have filed a qar against it (QAR 52953, but have had no reply to it. If you can shed any light on this, I'd appreciate it. [Posted by WWW Notes gateway]
1060.4	log half full	NNTPD::"[email protected]"		`Mon May 19 1997 14:03`	17
	There are two ways to produce "log half full". One way is migrating a file with a large number of extents (thousands). Defragment uses migration to coalesce extents. So running defragment helps prevent the problem before it gets too bad, but can directly cause the problem if a file is sufficiently fragmented. Workarounds to "log half full" were published in the patches area. If just a few files have more than 40000 extents (as shown by showfile -x) they can be dumped and restored or copied to another domain and back. Running defragment after the fragmented file is removed from the domain will ensure that there are large extents for the file when it is restored or copied back in. The underlying problem was fixed in steel and soon will be submitted to ptmin. The fix was extensive and will not be put out as a patch. [Posted by WWW Notes gateway]