Re: Logical volume management

From: Alexander Leidinger <Alexander_at_Leidinger.net>
Date: Sun, 20 Nov 2005 13:59:14 +0100
On Sat, 19 Nov 2005 16:02:16 +1100
Peter Jeremy <PeterJeremy_at_optushome.com.au> wrote:

> The other disadvantages I see are:
> - All the cylinder groups headers are pre-allocated.  AFAIK, UFS2 avoids
>   pre-allocating the inodes but still reserves the space for them.  A
>   large virtual filesystem will have significant overheads even if it
>   only has a small amount of real data.
> - UFS assumes that all the space is physically available and allocates
>   blocks so as to (hopefully) maximize performance.  This is likely to
>   lead to significant fragmentation with lots of partially utilised
>   data chunks.

I think those are the reasons why Sun decided to integrate the "new" VM
and the new FS code into one black box called ZFS (to prevent someone
from using a plain UFS with the new VM and then moan because of the
non-optimal performance).

Bye,
Alexander.

-- 
               Speak softly and carry a cellular phone.

http://www.Leidinger.net                       Alexander _at_ Leidinger.net
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Received on Sun Nov 20 2005 - 11:59:30 UTC

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