Re: [EXIM] MFS mount spool

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Author: Tabor J. Wells
Date:  
To: Richard G. Duvall
CC: exim-users
Subject: Re: [EXIM] MFS mount spool
On Thu, Jun 17, 1999 at 03:50:05AM -0700,
Richard G. Duvall <rgduvall@???> is thought to have said:

> Yes, but the drive is cranking like mad! Should I install a different
> drive on a different SCSI bus just for spooling?
>
> It's even making authentication slow, and it is running on a Pentium II,
> 400Mhz with 128MB Ram.
>
> It's just unbearable the amount of time it takes to authenticate. Alot of
> time when I am running PC-Pine over the same ethernet, it times out. this
> is really annoying...
>
> I tried installing a different drive just for spooling on the same scsi
> bus, and this helped tremendously. But, I still get timeouts with
> PC-Pine, and iostat is reporting TONS of activity on both drives (spool,
> and the other drive which contains root filesystem, and where mail files
> are being stored).
>
> Our weakest link seems to be the speed of our hard drives, and it is
> slowing authentication down. What can we do to remedy this problem? We
> are running that 50 pin scsi card from BusLogic, and one of those 9 gig
> Segate drives, in which we have to use an adaptor thingy to make the cable
> work on it (counted 68 pins on the drive). Then, the other drive where I
> am spooling the stuff is 50 pin, and the cable plugs right into it.
>
> Do I need to get one of those faster SCSI cards from Adaptec that plug
> directly into that kind of drive without an adaptor thingy. Would that
> make it faster?
>
> Sincerely,
>
> Richard G. Duvall


Ok. It sounds like you've taken a fast/wide SCSI drive and plugged it into
a narrow SCSI adaptor. That's going to significantly affect the speed of
your disks. Also you say it's a 9g Seagate, which kind? Is it a Barracuda
or Cheetah? Barracudas spin at 4000 RPM, Cheetahs at 10,000 RPM. I
wouldn't use a 9g Barracuda in an I/O intensive environment. It just takes
too long to seek across the drive.

Also you can improve your performance quite a bit but locating your spool
on a separate filesystem. It doesn't necessarily have to be a separate
controller, but that wouldn't be a bad idea if you're doing a lot of mail.

At Shore what we've got is two 4g drives stripped together and then
mirrored (RAID 0+1) using RAID software (Sun's Solaris Disk Suite). I
don't know what options like that exist for you in your OS of choice, but
you might look into doing something like that as well, if necessary.

Tabor

-- 
___________________________________________________________________________
Tabor J. Wells                                             twells@???
Systems Administration Manager  Just another victim of the ambient morality
Shore.Net  --  High quality Internet access and hosting services since 1993


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