[squid-users] cache_dir sizes question (two new 70GB disks)

Hello guys,
currently, I have
   Mean Object Size: 21.66 KB

At the moment, I have 3 SCSI disks, 36 GB, 10K, so my cache_dir is:

   cache_dir aufs /cache/cache1 28000 60 256
   cache_dir aufs /cache/cache2 28000 60 256
   cache_dir aufs /cache/cache3 28000 60 256

There is no RAID. Because my Mean Object Size is 21 K, it means, there
is 28000000/21/60/256 = 88 files in each second-level directory (which
is few, I didn't expect the mean object size so high, but I don't think
it is a disadvantage).

My boss just gave me another two SCSI disk, 70 GB, 15K - he wants me to
maximise "Byte hit ratio" and I believe to have bigger cache is the
right way (I have already set LFUDA replacement policy etc).

I am going to add these two disk to the box, how would you use them, so
you get the best performance?

1) add 2 new cache_dirs
    56 GB cache on every from these two 70GB disks?

   cache_dir aufs /cache/cache4 56000 60 256
   cache_dir aufs /cache/cache5 56000 60 256

If my mean object size stays 21 kb, there will be average 173 files
(56000000/21/60/256) in each second-level directory.

2) add 4 new cache_dirs
    two 28 cache on every from these two 70GB disks?

   cache_dir aufs /cache/cache4 28000 60 256
   cache_dir aufs /cache/cache5 28000 60 256
   cache_dir aufs /cache/cache6 28000 60 256
   cache_dir aufs /cache/cache7 28000 60 256

I prefer the first solution, but does it realy matter?

I also wonder if there will be any trouble caused by my mix of three
36GB disk 10K only and two 70GB disks 15K working together...

Thank you,
Marji
Received on Fri Dec 10 2004 - 00:27:34 MST