On Fri, 2 Apr 1999, Jeff Hill wrote:
I've got a web server putting out just 10K pages and about 25MB a day.
Not much, but it's growing quickly and does get bogged down at certain
times during the day (seems about half is served between 2:30 and 4:00
PM).
Which is the better upgrade, more RAM or going to SCSI?
That's impossible to answer given the information provided. As a rule of
thumb, I'd say adding RAM would be the best choice, but there are always
complications.
First, try to determine where the bottleneck actually lies. Log on while
the system is bogged down. Run 'free' to see where the RAM is being used
and if you're dipping into swap, 'top' to get an idea how hard the CPU is
working, and so forth. If you can take the system offline for a while, try
running 'bonnie' and see what kind of disk throughput you're getting.
Linux is fairly conservative, sometimes paranoid, about things like IDE
settings. Using 'hdparm' I was able to significantly increase the speed of
my IDE disks. See http://www.tir.com/~sorceror/report.html;. I'd try this
(cautiously) before springing for new hardware. (Note that this 'report'
is on *old* hardware, so you should see *far* better numbers than I did.)
Currently, I'm running a P150 with 96MB RAM on a fast IDE drive (7200
RPM). I'm working on upgrading the server to slink with Apache-SSL.
For single disks, IDE is not significantly slower than SCSI, as long as
you're using DMA. Linux doesn't usually do that by default, so check with
'hdparm' and see how you're actually using the disks.
We only have about 250MB of web pages, and I think I might be better off
bumping RAM to something like 512MB rather than moving to SCSI (which
would cost about the same).
A someone else said, make sure your motherboard can actually use that
much RAM - if it can't cache it, it may be more trouble than it's worth.
Linux can still use it as ultrafast swap space if you apply a patch to the
kernel, but if RAM isn't the problem it's really a waste.
(even with the mysql and htdig databases I run on it). Additionally, if
I wait, I could move to SCSI with RAID rather than the basic ADAPTEC
2940UW that we are looking at.
Given the limited budget you have, you might be able to put in a couple
more IDE disks and do software RAID. It's not as fast as RAID-in-hardware,
but it's a lot cheaper.
Sincerely,
Ray Ingles (248) 377-7735 [EMAIL PROTECTED]
Any technology distinguishable from magic is insufficiently advanced.
- Anonymous' restatement of Clarke
