Date: Sat, 9 Nov 2002 23:38:34 -0500 From: Paul Mather <paul@gromit.dlib.vt.edu> To: Eugene Grosbein <eugen@kuzbass.ru> Cc: Chris BeHanna <behanna@zbzoom.net>, FreeBSD-Stable <stable@FreeBSD.ORG> Subject: Re: backups of SUPERBLOCK Message-ID: <20021110043834.GA3665@gromit.dlib.vt.edu> In-Reply-To: <3DCDDFB1.D49327C6@kuzbass.ru> References: <20021109231607.W9701-100000@topperwein.pennasoft.com> <3DCDDFB1.D49327C6@kuzbass.ru>
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On Sun, Nov 10, 2002 at 11:25:21AM +0700, Eugene Grosbein wrote:
=> > If you didn't do any custom tuning with newfs, it's likely that
=> >
=> > newfs -N -b 8192 -f 1024 # pre 4.6
=> >
=> > or
=> >
=> > newfs -N -b 16384 -f 2048 # 4.6 and up
=> >
=> > will be sufficient.
=>
=> Yeah. But this system was set up in times when newfs did not optimize
=> cyl/group ratio and I remember that I manually run
=> newfs with -b, -f and -c flags. Should I now worry about recovering those
=> values to get right output from newsf -N, or not?
=> And if I should, how can I obtain all real values?
You can use dumpfs to get the real values, e.g.:
dumpfs /dev/vinum/var | head -20
will tell you the information you're interested about.
Actually, it was using dumpfs that I realised that newfs on vinum
partitions does not appear to use the default block size of 16K, as
stated in the newfs man page. (It used 8K, with a 1K fragment size.)
So, when newfs'ing the filesystem, I manually set the block size and
fragment size to 16K and 2K respectively (and 32K/4K for another vinum
filesystem that holds mainly large files for FTP). (Was this a
mistake? Is there some magic to vinum using 8K/1K?)
Cheers,
Paul.
e-mail: paul@gromit.dlib.vt.edu
"Without music to decorate it, time is just a bunch of boring production
deadlines or dates by which bills must be paid."
--- Frank Vincent Zappa
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