[Gllug] Raw Partitions

[Nix]

On Thu, 17 Nov 2005, Steve Nelson stipulated:
> Thank you - amazing how you manage to sprinkle little gems in your
> emails.  I shall read this over lunch.

I'll give Peter this: he's very, very good at using Google.

It's a shame that he's suffering from the same disease I used to have,
of assuming that Google plus a suitable tone leads to knowledge.

I recovered after correcting someone on the operation of STREAMS based
on a bit of googling only to find when he laughed at me that I was both
wrong and `correcting' the guy who'd originally specced STREAMS for
SysV, oops. I resolved that day never to post unless I actually *knew*
what I was talking about, using Google only as a confirmatory tool.
Oddly enough my posting volume shrank almost to zero for the next
year; guess I hadn't known as much as I thought :(

>>   ''I have a RHES 3 system with the usual heavily patched RH
>>     kernel 2.4.21 and when I run Oracle 10 on it over GFS 6.0
>>     and there are crashes in the Oracle quorum manager using
>>     'raw'(8) devices wrapping GFS pools, as described in this
>>     link: [link omitted]. What can I do?
> 
> No - because that bears absolutely no resemblance to what I actually
> wanted - which is what I asked in the first email.  It also shows that
> you don't appear to understand how quorums work in Redhat
> Clustersuite.

This is the problem with Google. If a term like `quorum' is only used in
one tool you can be accurate enough: otherwise you risk making a fool of
yourself, as here when two quite different products use the same
terminology for different things (derived from a term of art, of
course)...

>>    * The 'raw' driver is likely to be somewhat unreliable, as
>>      well as being deprecated.
> 
> Wrong - I am using a 2.4 kernel - which you even seem to have
> understood, yet still insist raw is deprecated.

And indeed raw is quite safe in 2.4. What broke it was the moving of
non-metadata out of the buffer cache, IIRC, and now it is going
the way of dump(8) in 2.6.

>>    * Since both 'raw'(8)/'O_DIRECT' and AIO are optimizations,

AIO isn't an optimization, it's a completely different way of doing file
I/O from a userspace perspective (`wait' versus `don't wait').

-- 
`Holy Google, pray for us sinners now and in the hour of our job interview.'
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