[CentOS] Question about optimal filesystem with many small files.
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hhh735 at hotmail.com
Mon Jul 13 05:49:11 UTC 2009
>How many files per directory do you have?
I have 4 directory levels, 65536 leaves directories and around 200 files per dir (15M in total)-
>Something is wrong. Got to figure this out. Where did this RAM go?
Thanks I reduced the memory usage of mysql and my app it and I got around a 15% performance increase. Now my atop looks like this (currently reading only cached files from disk).
PRC | sys 0.51s | user 9.29s | #proc 114 | #zombie 0 | #exit 0 |
CPU | sys 4% | user 93% | irq 1% | idle 208% | wait 94% |
cpu | sys 2% | user 48% | irq 1% | idle 21% | cpu001 w 28% |
cpu | sys 1% | user 17% | irq 0% | idle 41% | cpu000 w 40% |
cpu | sys 1% | user 14% | irq 0% | idle 74% | cpu003 w 12% |
cpu | sys 1% | user 13% | irq 0% | idle 72% | cpu002 w 14% |
CPL | avg1 3.45 | avg5 7.42 | avg15 10.76 | csw 15891 | intr 11695 |
MEM | tot 2.0G | free 51.2M | cache 587.8M | buff 1.0M | slab 281.2M |
SWP | tot 1.9G | free 1.9G | | vmcom 1.6G | vmlim 2.9G |
PAG | scan 3072 | stall 0 | | swin 0 | swout 0 |
DSK | sdb | busy 89% | read 1451 | write 0 | avio 6 ms |
DSK | sda | busy 6% | read 178 | write 54 | avio 2 ms |
NET | transport | tcpi 3631 | tcpo 3629 | udpi 0 | udpo 0 |
NET | network | ipi 3632 | ipo 3630 | ipfrw 0 | deliv 3632 |
NET | eth0 0% | pcki 5 | pcko 3 | si 0 Kbps | so 1 Kbps |
NET | lo ---- | pcki 3627 | pcko 3627 | si 775 Kbps | so 775 Kbps |
>It is 1024 chars long. Witch want still help.
I'm usng mysam and according to: http://dev.mysql.com/doc/refman/5.1/en/myisam-storage-engine.html
"The maximum key length is 1000 bytes. This can also be changed by changing the source and recompiling. For the case of a key longer than 250 bytes, a larger key block size than the default of 1024 bytes is used. "
>I would not store images in either one
as your SELECT LIKE and Random will kill it.
Well, I think that this can be avoided, using just searches in teh key fields should not give these issues. Does somebody have experience storing a large amount of medium (1KB-150KB) blob objects in mysql?
>However I have not a clue that this is even doable in MySQL.
In mysql there is already a MD5 funtion: http://dev.mysql.com/doc/refman/5.1/en/encryption-functions.html#function_md5
Thanks for the help.
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