I aldready discarded Mark's reply, so I cannot forward it ... but he said he asked for more details and was told that the speedup issue involves SCSI I/O of some sort ... I've forgotten the specifics ... a topic way outside my expertise.
So while Chris was closer to the target than I, Mark really needs to post a more specific follopup to the list in order to get help.
At 09:30 AM 5/12/2004 -0500, Little, Chris wrote:
see, i took this to mean disk i/o. the next guy might take it as video i/o. vague questions lead to vague answers, eh?
> -----Original Message----- > From: Ray Olszewski [mailto:[EMAIL PROTECTED] > Sent: Tuesday, May 11, 2004 11:52 AM > To: [EMAIL PROTECTED] > Subject: Re: Optimizing I/O via kernel changes > > > At 11:30 AM 5/11/2004 -0400, Gosselin, Mark wrote: > >Hi List, > > > >I've been asked the following question by our VP of Development. > > > >Is there some kernel parameter (or parameters) that we can tweak to > >improve our I/O on a Linux Server?? > > > >Since I'm new to Linux, I figured someone one one of these > lists might > >have a concise answer to that > >question. Can we use the kernel tomincrease I/O rates, or > are we bound by > >hardware?? > > This question is too vague to elicit a meaningful answer. > Even assuming you > mean Mbps on an Ethernet by "I/O rates" (there are other > possible meanings, > of course), knowing whether your particular setup is hardware > or software > bound requires knowledge of your hardware and software ... > > what NIC? (if not 100 Mbps, mention speed) > what CPU? (type and speed) > how much RAM? > is the system *ever* using swap? > any relevant IRQ sharing? > > what Linux distro and version? > what Linux kernel ("uname -a")? > custom or stock kernel? > what NIC module and parameters? > what (if any) iptables rules are you running? > does "ifconfig" show any appreciable error rate? > > what relevant services are you running? > what "I/O rates" are you currently seeing? > if the relevant connectivity is not just Ethernet > (for example, if > it is a DSL connection to the Internet), what type and speed > of connection > is it? > how "busy" is the system during normal operation? > what % CPU use does "top" report? > what blocking ("load averages") does "uptime" report? > > Depending on the details of the response, there could be ways > to speed up > throughput, such as reducing the complexity of firewall > rulesets, tweaking > NIC module settings, rearranging IRQ assignments, conceivably > doing some > tailoring to specific service needs, possibly tailoring > packet size (MTU) > settings to a link layer other than Ethernet. > > As a general matter, you may want to look at the settings > described in > your kernel Documentation under > ./Documentation/networking/ip-sysctl.txt > and at the doc file in the same directory for your NIC. But > there is no > magic "faster" switch in the kernel (or at least none I know > of) that is > turned off by default (why would there be?). > > In practice, 100 Mbps Ethernet NICs under Linux seem to > deliver somewhere > between 50 Mbps and 80 Mbps on a sustained basis, depending > on things I'm > not sure of (kernel version? specific NIC hardware?). > > And, of course, if I have misinterpreted your use of "I/O > rates", this > entire response is meaningless for your purposes.
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