-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I'm working on building a cheap server for a disk/diskless network. right now i've got a compaq proliant, with (4) 550mb scsi drives. I would like to upgrade this to a total of around 100-500 gigs of scsi, with half being mirrored on a raid setup. i'm unsure of the cost of a scsi raid card vs ide raid (need to stfw), but doing a search for cheap/good used scsi drives, i'm looking at 2-300% more in cost over ide. since I've found isa ide controllers for $3, and 500 gigs of ide would run me under $500, what is the advantage of going scsi? I'm beginning to thing that starting with a later AT board and around a 500mhz chip then adding a pair of 250 gig ide drives w/ raid card will not only be cheaper, but give me better overall performance. Am I correct in this line of thinking? Joe - -- SuSE Linux 8.2 (i586) Kernel: 2.4.20-4GB / i686 | Posted from: Dora ~ 3:06pm up 0:37, 2 users, load average: 0.16, 0.23, 0.35 Goto, n.: A programming tool that exists to allow structured programmers to complain about unstructured programmers. -- Ray Simard nqs@tmcom.com | http://tigger.tmcom.com/~nqs/blogger.html -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2-rc1-SuSE (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQE/wUcXoS1S7SxfpzwRApAFAKCcpGxOehx2+BFsrQYna/VIW41dpACgsFOQ 6AKsG7r4l5P/npMGxttUciI= =lrwC -----END PGP SIGNATURE-----
Joe Dufresne wrote:
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I'm working on building a cheap server for a disk/diskless network. right now i've got a compaq proliant, with (4) 550mb scsi drives. I would like to upgrade this to a total of around 100-500 gigs of scsi, with half being mirrored on a raid setup. i'm unsure of the cost of a scsi raid card vs ide raid (need to stfw), but doing a search for cheap/good used scsi drives, i'm looking at 2-300% more in cost over ide. since I've found isa ide controllers for $3, and 500 gigs of ide would run me under $500, what is the advantage of going scsi?
I'm beginning to thing that starting with a later AT board and around a 500mhz chip then adding a pair of 250 gig ide drives w/ raid card will not only be cheaper, but give me better overall performance. Am I correct in this line of thinking? for something on the cheap without a large amount of users connecting or a large database...yes, you are correct. For serious use and heavy, sustained i/o, scsi is still better.
Joe - -- SuSE Linux 8.2 (i586) Kernel: 2.4.20-4GB / i686 | Posted from: Dora ~ 3:06pm up 0:37, 2 users, load average: 0.16, 0.23, 0.35
Goto, n.: A programming tool that exists to allow structured programmers to complain about unstructured programmers. -- Ray Simard
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On Sun, 2003-11-23 at 18:47, Joe Dufresne wrote:
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I'm working on building a cheap server for a disk/diskless network. right now i've got a compaq proliant, with (4) 550mb scsi drives. I would like to upgrade this to a total of around 100-500 gigs of scsi, with half being mirrored on a raid setup. i'm unsure of the cost of a scsi raid card vs ide raid (need to stfw), but doing a search for cheap/good used scsi drives, i'm looking at 2-300% more in cost over ide. since I've found isa ide controllers for $3, and 500 gigs of ide would run me under $500, what is the advantage of going scsi?
I'm beginning to thing that starting with a later AT board and around a 500mhz chip then adding a pair of 250 gig ide drives w/ raid card will not only be cheaper, but give me better overall performance. Am I correct in this line of thinking?
Joe - --
ATA is getting better, but scsi is still superior. Most ATA (ide) drives are designed for 20% duty cycle, SCSI 100%. On a ATA bus only the Master or Slave can be active at a given time. That is why some ATA raid controllers (ie. 3ware at least) only support master drives. SCSI does not have a similar limitation. ATA drives do not have a command queue. IIRC SCSI has a 7 deep command queue. I'm not sure how the command queue is used, but I know it effects performance and cost. Serial ATA is another good choice. I don't know what duty cycle it is designed for, but it does not have the master/slave issues and IIRC it has a 3-deep command queue. Greg -- Greg Freemyer
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Carlos E. R. wrote: | The Monday 2003-11-24 at 10:57 -0500, Greg Freemyer wrote: | | |>Most ATA (ide) drives are designed for 20% duty cycle, SCSI 100%. | | | Please, clarify: what is "duty cycle" for a HD? I can't recollect what it | might be right now. | | Assuming it's the same as on a welder, a 20% duty cycle means you can run the drive for 2 minutes, then wait 8. except in this case id change minutes to milliseconds Joe - -- SuSE Linux 8.2 (i586) Kernel: 2.4.20-4GB / i686 | Posted from: Dora ~ 5:42pm up 0:52, 4 users, load average: 1.29, 1.35, 0.88 "I went to the hardware store and bought some used paint. It was in the shape of a house. I also bought some batteries, but they weren't included." -- Steven Wright nqs@tmcom.com | http://tigger.tmcom.com/~nqs/blogger.html -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2-rc1-SuSE (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQE/wrQPoS1S7SxfpzwRAtK+AKC2p3i7/bFKfMLObrJh+kuWSoIHaQCfTiaP rBBDdvVfLc2Xyq++qK44SZ0= =7R1m -----END PGP SIGNATURE-----
The Monday 2003-11-24 at 17:44 -0800, Joe Dufresne wrote:
| Please, clarify: what is "duty cycle" for a HD? I can't recollect what it | might be right now. | |
Assuming it's the same as on a welder, a 20% duty cycle means you can run the drive for 2 minutes, then wait 8.
except in this case id change minutes to milliseconds
Can't be that easy... I know what "duty cycle" usually means, for example in a waveform. But not for HDs, I don't. Duty cycle in this context must mean something more complex than that. You can measure "continuous throughput", meaning continuous read from contiguous sectors up to many megabytes. It is a number given by manufacturers. In a real world scenario, files may be fragmented, another file reads may come in the middle, etc. But that is another issue, more OS oriented. For a HD you give... hold on, a sample from Seagate: PERFORMANCE Maximum Internal Transfer Rate (Mbytes/sec) 54.5 Average Sustained Transfer Rate (Mbytes/sec) >14.5 Multisegmented Cache (Mbytes) Average Seek (msec) 2 Average Latency (msec) 8.9 Spindle Speed (RPM) 5400 But a search of the word "duty" finds nothing :-? -- Cheers, Carlos Robinson
participants (4)
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Carlos E. R. -
Greg Freemyer -
Joe Dufresne -
pheonix1t