I am experimenting with lessfs on Ubuntu 12.04 using the configuration
suggested by Mark at http://www.lessfs.com/wordpress/?p=707, but with
lessfs 1.5.12 and hamsterdb 2.0.4 (and snappy 1.0.5). I have used Mark's
lessfs.cfg file (http://www.lessfs.com/wordpress/wp-content/lessfs.cfg)
but as I am testing with a single-processor VM I set MAX_THREADS=1. The
machine has 1GB RAM.
I set about copying (rsync) some data (a lot of files, mostly quite
small Word or pdf files) into the lessfs mount. Things go quickly for a
while (and there are pauses every so often which I guess are when lessfs
flushes data to disk) but then become very slow indeed (say 1 x 30K file
per second), and never speed up again.
This seems similar to the problems in a previous posting
but that was where tokyocabinet was being used, and the suggestions
relate to _BS configuration options which don't seem apply when using
hamsterdb: man lessfs states: 'The hamsterdb database does not require
the _BS lines since hamsterdb does not use hash databases'. Does this
apply to all *_BS configuration options, I presume so because none are
set in Mark's lessfs.cfg?
Size of underlying datastore (sudo du -h --summarize /data): 589MB
Size of stored files (sudo du -h --summarize /mnt/less): 869M (62 min to
Number of stored files (sudo find /mnt/less -type f | wc -l): 22675
Can anyone suggest why lessfs is so very slow on my system and how I can
I have tried starting lessfs with '-o
big_writes,max_read=131072,max_write=131072', or not: doesn't seem to
make any difference to performance, maybe the setting BLKSIZE=131072 in
lessfs.cfg means these settings are used anyway?
Thanks for any help
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