Date: Thu, 8 Feb 2001 11:34:06 +1100 From: Greg Lehey <grog@lemis.com> To: Dan Phoenix <dphoenix@bravenet.com> Cc: Andrew Reilly <areilly@bigpond.net.au>, Alfred Perlstein <bright@wintelcom.net>, Andre Oppermann <oppermann@monzoon.net>, Matt Dillon <dillon@earth.backplane.com>, Rik van Riel <riel@conectiva.com.br>, Mike Silbersack <silby@silby.com>, Poul-Henning Kamp <phk@critter.freebsd.dk>, Charles Randall <crandall@matchlogic.com>, Jos Backus <josb@cncdsl.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: vinum and qmail (RE: qmail IO problems) Message-ID: <20010208113406.C38406@sydney.worldwide.lemis.com> In-Reply-To: <Pine.BSO.4.21.0102071309260.9863-100000@gandalf.bravenet.com>; from dphoenix@bravenet.com on Wed, Feb 07, 2001 at 01:16:44PM -0800 References: <20010207141225.A769@gurney.reilly.home> <Pine.BSO.4.21.0102071309260.9863-100000@gandalf.bravenet.com>
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On Wednesday, 7 February 2001 at 13:16:44 -0800, Dan Phoenix wrote:
> On Wed, 7 Feb 2001, Andrew Reilly wrote:
>> On Tue, Feb 06, 2001 at 12:13:57PM -0800, Alfred Perlstein wrote:
>>> * Andre Oppermann <oppermann@monzoon.net> [010206 12:07] wrote:
>>>> Does sendmail even use fsync()?
>>>
>>> It better. :)
>>
>> Quick grep of the sendmail sources shows most of the six fsync
>> calls protected by a flag (SuperSafe && or nofsync &&). I don't
>> know what circumstances can provoke either of those flags to be
>> zero, but if they can be, then it mightn't be doing any fsyncs.
>
> I went over to postfix to see if it did better.....in fact it did on
> freebsd but still same problem with I/O. SOlution from talking to
> some people late last night would be to add another harddrive and
> stripe it with another drive using vinum. As you all know IDE does
> not do multitasking unlike scsi. My question is this vinum
> product...i beleive the superceder of ccd....taking another
> harddrive and striping it with the root ide drive would in theory
> destroy all contents of first IDE? Or can this volume manager take
> say a partition of first ide drive and made to work with another ide
> drive? Trying to figure out at this point whether concept is 2 other
> drives striped together say..using raid 0 or I can get away with
> just one other one. Thx in advance.
At the moment there are two issues:
1. Vinum requires that all file systems be made out of subdisks in a
"drive", which is really a partition. A drive has 265 sectors of
config and label information at the beginning, so unless you have
this space available, you can't turn a ufs partition into a Vinum
object. You can convert the first file system after swap to Vinum
by shrinking the swap and moving the start of the drive to 265
sectors before the beginning of the file system.
Even so, you wouldn't be able to stripe things in this
configuration, because striping rearranges the blocks on disk.
But I suspect that with ufs, striping won't buy you much over
concatenation, which *would* work in this scenario.
I'm planning to change things so that Vinum can import external
objects such as ufs partitions, for exactly this reason. But I
still want to be able to have at least one Vinum drive on each
spindle (i.e. physical drive), because Vinum is location
independent: you can move spindles with Vinum drives on them to
different locations (device names), and Vinum will still
understand the configuration. This requires information on the
spindle itself, of course.
2. The released version of Vinum still doesn't support a Vinum root
file system. I'm planning to work on that, but it'll take a
while.
Greg
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