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Dual Mirrors on PERC3 SC?
- Thread starter rswift
- Start date
I have not used the SC model, but it should not make any difference.
The issue you may run into is if you have many disk in an array. Each u320 disk can add 60-80 Meg/sec to the channel. At 60 Meg the channel will saturate with more than 5 disks, figuring at the high end of 80 (burst rate), the channel saturates at 4 disks. At saturation the SCSI bus will clamp down on the data accepted on the bus, so the throughput will not increase with added disks over the fore mentioned numbers.
Example, using 80 Meg rate(unrealistic) to keep the number of drives even...
So basically you could have a raid 10 array on single channel, of 2 dives, mirrored, by another two, at which point anymore drives will not help throughput.
With two channels you would not reach saturation, with raid 10, with 4 drives, mirrored by another 4; which would give you much more performance, than the single channel adapter
The issue you may run into is if you have many disk in an array. Each u320 disk can add 60-80 Meg/sec to the channel. At 60 Meg the channel will saturate with more than 5 disks, figuring at the high end of 80 (burst rate), the channel saturates at 4 disks. At saturation the SCSI bus will clamp down on the data accepted on the bus, so the throughput will not increase with added disks over the fore mentioned numbers.
Example, using 80 Meg rate(unrealistic) to keep the number of drives even...
So basically you could have a raid 10 array on single channel, of 2 dives, mirrored, by another two, at which point anymore drives will not help throughput.
With two channels you would not reach saturation, with raid 10, with 4 drives, mirrored by another 4; which would give you much more performance, than the single channel adapter
Correction...
With two channels you would not reach saturation, with raid 10, with 5 drives, mirrored by another 5, (drives divided evenly over two channels); which would give you much more performance, than the single channel adapter
With two channels you would not reach saturation, with raid 10, with 5 drives, mirrored by another 5, (drives divided evenly over two channels); which would give you much more performance, than the single channel adapter
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