I do'nt wanna to get your mails again!!Fw: Squid on IDE

-----原始郵件-----
寄件者: William Stucke <William.Stucke@zanet.co.za>
收件者: squid-users@ircache.net <squid-users@ircache.net>
日期: 1998年10月26日 PM 06:58
主旨: RE: Squid on IDE

>On Monday, October 26, 1998 9:28 AM, Marc van Selm
>[SMTP:marc.van.selm@nc3a.nato.int] wrote:
>> At 12:03 PM 10/23/98 -0400, Mike.Richards wrote:
>> >Gustavo,
>> > DO NOT USE IDE for heavy disk IO application servers, e.g. Sun Ultra
>> > 10,
>> > it will/does not perform anywhere near SCSI.....
>
>Usually, but not always true - beware of the SCSI manufacturers' propaganda
>;-) For a single disk, the raw speeds are as follows : (Data from various
>sources, some slightly contradictory!)
>
>ESDI: 3 MB/s - very old stuff!
>IDE (= ATA): 4 - 12 MB/s - 1981 to ~1990
>EIDE (ATA Mode 2): 17 MB/s - 1994
>Ultra ATA (Mode 4); 33 MB/s - 1997
>Ultra ATA/66 - brand new: 66 MB/s
>SCSI - "standard" controller: 5 MB/s
>SCSI - Fast: 10 MB/s
>SCSI - Fast & Wide: 40 MB/s
>SCSI - Ultra: 20 MB/s sustained, 80 MB/s burst rate
>
>However, if you have multiple disks, then SCSI scores, because it is
>capable of multi-processing - while one disk is doing a seek, another can
>be doing a read. What this means to you and me is that SCSI has no
>significant performance benefit for the "standard off the shelf" version
>of either technology. In fact, it can even be slower, and is significantly
>more expensive. However, for a machine which is especially used for
>disk-intensive applications, and therefore has multiple drives, SCSI is
>definitely better.
>
>> Also make sure your machine isn't swapping to much. If you say you have
>> not
>> very much mem I expect this is your main problem.
>>
>> Squid keeps a lot in memory (and becomes very fast) but if it has to swap
>> it
>> becomes very slow...
>
>VERY true. Remember that your RAM is somewhere between 300,000 and
>1,000,000 times faster than the disk. If you are swapping to disk, then
>this will REALLY slow you down. Depending on your OS and application, plan
>on having 128 MB and up of RAM.
>
>Up to a limit, the amount of RAM is much more important than the CPU speed.
>For example, considering Windows 95 running typical office applications: A
>Pentium 100 with 64 MB RAM is significantly faster than a 200 MHz Pentium
>with 16 MB of RAM. Over ~55 MB it doesn't make a real difference in this
>example. Other cases will require more RAM, e.g. a server of almost any
>sort.
>
>Regards,
>
>William Stucke
>ZAnet Internet Services (Pty) Ltd
>William.Stucke@zanet.co.za
>+27 11 465-0700
>
Received on Mon Oct 26 1998 - 06:45:41 MST