this is a webserver ......i am trying to figure out if cpu increase or
scsi drives is better in this situation. Right now...that is a big
decision because there are approx 30 fbsd webservers ....not all showing
high IO from vmstat...just the ones with the highest uptime.
More of a decision is a cost-effective one. Rather than buying a new
machine to bring LA down would increasing IO or cpu give the servers
more perf so as to not buy new servers each time......
thanks for your comments....not sure why iostat not giving correct
readings, but just glad i know...thanks again.
On Mon, 5 Mar 2001, Matt Dillon wrote:
> Date: Mon, 5 Mar 2001 16:31:45 -0800 (PST)
> From: Matt Dillon <[EMAIL PROTECTED]>
> To: Dan Phoenix <[EMAIL PROTECTED]>
> Cc: [EMAIL PROTECTED]
> Subject: Re: systat -vmstat or iostat IO help
>
> :systat -vmstat
> :
> :Disks ad0 acd0 fd0 md0 89 ofod intrn
> :KB/t 4.35 0.00 0.00 0.00 85 %slo-z 61952 buf
> :tps 13 0 0 0 104 tfree 42 dirtybuf
> :MB/s 0.05 0.00 0.00 0.00 36095 desiredvnodes
> :% busy 100 0 0 0 58692 numvnodes
> :
> :well vmstat showing 100% busy and iostat showing 10% busy......
> :IO an issue here or not?
> :...
> :Dan
>
> systat -vmstat is correct. I usually use 'systat -vm 1'. If you see
> 100% busy for more then a few seconds then the disk is saturated
> (almost certainly seek-limited). Solutions depend on what the system
> is doing. Mail systems are the least scaleable, requiring you to
> add additional disks for spools or a stripe, or additional machines
> and use an MX round robin. Most other services can be scaled well
> simply by adding memory or cpu. SCSI disks usually do better then IDE
> in seek-limited situations. Higher-RPM disks can make a big difference
> too.
>
> -Matt
>
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