Defrag Software

Vincent Trouilliez vincent.trouilliez at modulonet.fr
Fri May 20 13:04:26 UTC 2005


> For what it's worth, you don't need to defrag database filesystems on
> any OS. At least not if they're competently administered.

Ah, sorry, this was a bad example then. There must be cases where
framentation can occur, no ? I don't know, for multimedia maybe ? 
Whatever...

> Most commercial databases need a set of disks for performance reasons.
> The one I look after at work has a RAID 10 across ten disks [1], and
> that isn't large by commercial standards. It certainly doesn't run into
> terabytes!

I guess I was thinking/picturing big servers/main frames here, not
"SOHO" stuff ;o)
The only ones I ever saw, was last summer, when I worked for a month at
Bull, assembling and configuring their machines, well, learning with a
technician teaching me really, basically IBM H/W with AIX. I was
learning on their smallest offering, a 42U (IIRC, was about 2meter high)
cabinet, a couple 8 CPUs nodes (PL820R anyone ?), each with 6 drives
IIRC, and of course 2 or 3 disk arrays/DAS (can't remember... 14 disks
each ?) and a few more similarly sized cabinets with no nodes, just
fully loaded with disks. Can't remember the size, I think it was 73GB
15K rpm drives. So rougly 100 disks or so per cabinet, 7.5 TB just for
one little cabinet ! :-O  We used RAID5, so I don't think we lost much
capacity, compared to RAID1 anyway...
Nice machines (if just a tad noisy...), too bad I stayed only 4 weeks
there, hardly enough time to learn anything properly really :o(
Would you believe it, instead of AIX, they also offered Mandrake on
these monsters, upon explicit customer request of course.
Would be fun to see Ubuntu run these things, but does Ubuntu support/run
on IBM servers ? 

But about fragmentation on these, no idea... can't even remember the
file system used. I just remember that we tested the disk of the nodes
with 'dd', then created a few RAID 5 devices to check that the DAS were
working, and that's about it... ready for 24 hours of stress-testing. 

> That's *why* you need all those disks.

I wonder what the performance of the DAS was... if only I knew how to
test it back then ! Too late now :o(


--
Vince, wishing he were still working there...





More information about the ubuntu-users mailing list