[nycbug-talk] File Backed Disks- Speed Issues

Trish Lynch trish at bsdunix.net
Thu Sep 28 15:17:37 EDT 2006

On Thu, 28 Sep 2006, Isaac Levy wrote:

> During the FreeBSD 4.x days, (wow what an era), file-backed disks
> were snappy, with little overhead, no? (vn(4) and vnconfig(8),
> respectively)
> --
> In the immediate future, I'm taking some jailing systems back to just
> running jails on the filesystem, (and partitioning, yuck), but in the
> meantime does anyone have any thoughts on the subject?  It simply
> seems like the file-backing part of the memory disk implementation
> was slapped on, or perhaps is just cruft left over from the 5.x era?
> Hrm...


 	I'm not sure they ever were really "snappy", but I think you've 
got two things to content with.... not any optimization in the code they 
currently use now to do file backed storage devices *and* the fact that 
the size of them has to be much larger than what you used to use back in 
the 4.x days anyway (I know all my filesystems are definitely much larger 
than then.....

 	File out who the maintainer of the code is (done by looking in the 
source for the command), and contact them directly on this issue, they may 
have some kind of system tuning directly involved with this, either 
changing block sizes or anything like that in the filesystem creation..... 
when you get an answer, let us know!


Trish Lynch					   trish at bsdunix.net
Key fingerprint = 781D 2B47 AA4B FC88 B919  0CD6 26B2 1D62 6FC1 FF16

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