Skip site navigation (1)Skip section navigation (2)
Date:      Sat, 23 Oct 2004 16:10:41 +0200
From:      des@des.no (=?iso-8859-1?q?Dag-Erling_Sm=F8rgrav?=)
To:        Clifton Royston <cliftonr@lava.net>
Cc:        hackers@freebsd.org
Subject:   Re: Relative performance of swap-backed MFS vs. regular UFS?
Message-ID:  <xzpis91h6e6.fsf@dwp.des.no>
In-Reply-To: <20041022223238.GA12502@tikitechnologies.com> (Clifton Royston's message of "Fri, 22 Oct 2004 12:32:40 -1000")
References:  <20041022223238.GA12502@tikitechnologies.com>

next in thread | previous in thread | raw e-mail | index | archive | help
Clifton Royston <cliftonr@lava.net> writes:
>   For a large temporary file system which must hold short-lived files,
> mostly small but occasionally several very large ones (e.g. 100MB+), is
> it better for performance and stability if this file system:
>
>   1) resides on a swap-backed MFS and trusts the OS to swap out
> low-priority blocks if needed under RAM pressure, or
>
>   2) on a regular UFS and trusts the OS to buffer as many blocks as
> possible into RAM when RAM is free?

the former, provided you have enough RAM.  A swap-backed MFS will only
swap out when it has to, while a UFS will always write out changes
after a while.

>   I temporarily enlarged it to 256MB which is working, but as I worked
> out the worst case scenario, I realized it really would need to be
> nearly 1GB to handle multiple zip-bombs each hitting the 100MB size
> limit.  This makes me wonder if it's wise to specify a 1GB MFS on a
> system with only 1GB RAM, or wiser to just revert to a regular file
> system?

RAM is cheap.  Toss in a couple extra gig and set up a 2 GB MFS.

DES
--=20
Dag-Erling Sm=F8rgrav - des@des.no



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?xzpis91h6e6.fsf>