Different blocksize

[Praveen Bezawada]

Hi
We have observed that the average file size on different filesystem is different, so we are planning to have different blocksizes for each of the filesystem. Filesystem where largefiles exists we plan to have a block size of 8k and on others 4k.
We hope to save space and gain some performance benefit through this.
Is this worthwhile ? Will we gain what we intend to ?

...BPK...

[A. Clay Stephenson]

If this is vxfs, I don't think you are going to see any difference. In general you are going to see much more important and significant results if you stripe you data well. Vxfs filesystems seem to do best when the LVOL stripe size is 64K regfardless of the filesystem block size. Also, larger block sizes in vxfs filesystems don't waste space as they do in hfs or s5 filesystems.

If this is hfs, you may see some perfomance differences depending upon filesystem blocksizes but nowadays vxfs filesystem performance is almost always superior to that of vxfs.

[Peter Kloetgen]

Hi Praveen,

which type of file system(s) are you using? I don't think that you will save much disk space for the reason of fragment usage, but you will be able to speed up reading processes. Increasing block size makes sense when your average file size is very big and when you have a high disc usage.


Allways stay on the bright side of life!

Peter

[Tom Geudens]

Hi,
Playing with blocksizes might (in my experience be usefull) in 2 cases :
1. Database filesystems. You benefit from having blocksize of these filesystems "in sync" with the size used within the database itself.
2. Largefile filesystems. The gain here is not necessarily performance, but the fact that you can run into vgcreate/lvcreate limits when the filesystems become very large.

Hope this helps,
Tom Geudens

[harry d brown jr]

I love to micro-manage my systems, NOT! As far as saving any space, you will SPEND more money trying to figure out how to manage the space, so buy more disk, and save yourself the headaches. In the 70's and 80's we Micro-Managed our systems because the cost of a megabyte was HUGE, like over $700.00. Today its less than 1 US penny, like $0.006.



live free or die
harry

[Wodisch]

Hello Praveen,

we had a very similiar discussion over there:
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x6dc0c8ecad09d6118ff40090279cd0f9,00.html

and my point of view is still unchanged ;-)

Regards,
Wodisch