Re: [squid-users] Squid limits and hardware spec

> >YOu might also want to change your L1 directories, for a 90GB cache,
> >only having 16 L1 directories may be overkill.

On 02.12 21:22, Martin Marji Cermak wrote:
> Thank you, you are right.
> At the moment I have
> cache_dir aufs /cache 92000 16 256
> because I have 3 x 36GB SCSI disk behind a RAID0 (strip) contoller
> (seems to be just one disk).
> Yes, I know, raid is bad, but a RAID 0 controller is the only controller
> I have had since today :-)

Many RAID controllers can be used as simple IDE or SCSI controller.
Did you try using those disks this way?

> So I am going to connect there 3 disks to the new controller (no RAID)
> tomorrow with this settings:
>
> cache_dir aufs /cache1 30000 60 256
> cache_dir aufs /cache2 30000 60 256
> cache_dir aufs /cache3 30000 60 256
>
> (30000 is roughly 80% of the 36 GB disk, so I am right, right?)

yes, I have exactly these numbers on 36GB disks, however

> I am just sorry about my actual, full 92 GB cache - when I remove the
> three disks from the strip, I will have to reformate them and start with
> empty caches (it took more than 3 days to fill up this 92 GB cache).

you should get more disks - effective cache should be able to store 1
week's traffic. In such case, your setting of 50MB files max could be just
good for you (just check one week logs, what's the maximum file size
fetched more than once. That may not be the same file but can help you).

> The only way how to save some cached data is:
> - change my actual cache_dir aufs /cache 92000 16 256
> to cache_dir aufs /cache 30000 16 256
> and start Squid. It removes 62 GB from the cache.

yes, that is probably the only way. But it will take some time.

> >Just out of curiousity, what is your cache's filesystem? Ext3? reiserfs?

> I had reiserfs (with noatime) but it seemed too slow. I changed it to
> ext3 (noatime), which was supposed to be quicker according to the
> "Squid, the definitive guide" book, there are benchmarks and ext3 has
> much better throughput.

hmm??? I always thought reiserfs or xfs are much better than ext2/ext3 for
this use (many small files)

> Finally, I decided my Squid box is going to be stable (good hardware,
> UPS) and decided for ext2 with noatime.

note that in case of crash the fsck may tahe ages,

> >Do you expect to have more _large_ files or more small files? I use
> >reiserfs. (anticipate more small files caches)
> I do not know. I will have to get some stats, somehow. Is this info
> stored somewhere in Squid cachemgr info pages by any chances?

cachemgr will give you the mean object size, it will be 10 to 15kB and
this will proabbly tell you that for one 50MB file you have thousands of 1
kB files :)

> >>cache_mem 200 MB

> 14:11:52 up 1 day, 5:35, 1 user, load average: 2.04, 2.17, 2.25
> 45 processes: 41 sleeping, 4 running, 0 zombie, 0 stopped
> CPU states: 25.9% user, 74.1% system, 0.0% nice, 0.0% idle
> Mem: 1551284K total, 1520332K used, 30952K free, 109912K buffers
> Swap: 979956K total, 6200K used, 973756K free, 478308K cached
>
> PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND
> 13742 root 15 0 689M 687M 4020 R 90.0 45.4 377:58 squid
> 15497 root 16 0 940 940 748 R 8.4 0.0 0:02 top
> 13754 root 9 0 689M 687M 4020 S 0.4 45.4 0:20 squid

that means 200MB is acurate with your old setting (do I remember right
that you user 40GB of disk space?)

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