On Sunday 28 February 2010, Jon LaBadie wrote: >On Sun, Feb 28, 2010 at 10:59:23AM -0600, Dustin J. Mitchell wrote: >... > >> Yes, I just added this warning. Some refinement may be in order, so >> let me know what you think. >> >> The problem is that Amanda's fallback_splitsize defaults to 10M, and >> I've seen a number of users recently who are using this splitsize for >> multi-terabyte dumps, without knowing it. This generates *terrible* >> performance on backup, since the tape drive has to write tens or >> hundreds of thousands of filemarks, and also on recovery, since the >> recovery app must seek to and read from each of those many thousands >> of files. >> >> This is usually due not to a "fallback" in an error condition, but to >> misconfiguration. The splitsize parameters are *very* confusing! >> >> So the new warning is intended to alert folks such as yourself to the >> potential misconfiguration. It's just a warning, so Amanda will >> continue to run as before, but you really should fix it. To fix it, >> do one of: >> * set split_diskbuffer properly >> * raise your fallback_splitsize to something larger than 0.001 * >> tape-length * set fallback_splitsize to 0 > >... > >> Amanda always uses the tape_splitsize for FILE-WRITE dumps. It does >> the same for PORT-WRITE, but if split_diskbuffer is not set, which is >> the case on your system, then it uses fallback_splitsize instead (with >> its default of 10M), with no notice of the "fallback". >> >> So what if I changed the warning to read >> >> WARNING: shop /home: fallback_splitsize of 10240k < 0.1% of tape >> length and may create >1000 parts; set split_diskbuffer or increase >> fallback_splitsize > >Is this a case where verbosity is a positive? > > >WARNING: shop /home: fallback_splitsize of 10M is < 0.1% of tape length. >This may create > 1000 parts, severely degrading backup/restore > performance. To remedy, create/set a split_diskbuffer or increase > fallback_splitsize See <appropriate_URL> for more information. > >jl
Yes I think so Jon, but in my case I have over 800GB of /dumps available, so this particular item somewhat resembles a cry of wolf, when its just a termite, which I have to call for tomorrow. Its been about 20 years since we've had it done, and we just discovered some tunnels on the music room wall, same place as 20 years ago. Persistent critters. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If you're constantly being mistreated, you're cooperating with the treatment.
