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15k SATA drives?

B

Brown-Bomber

n00b
Joined
Mar 3, 2007
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I was reading that SATA III might be made available later this year or early in 2008. If that holds true do you think we will see 15k rpm SATA drives?
 
Well, only if WD makes them. As far as I know, WD is the only company that makes SATA drives faster than 7k2 because they don't have a SCSI line of drives. Theres no point for the other makers to venture in to the SATA realm when the primary buyers of such drives are enterprise buyers and use SCSI, also why make a drive to compete with your own product if you will. I suspect SAS will shake things up a bit when it proliferates, and we might start seeing 15k drives accessible to the enthusiast user without the need for a scsi controller card.
 
If you have a spare 4x PCIe slot and about $500 you can get SAS with at LSI Logic SAS3041E-R and a 15k cheetah (ST336754SS). :rolleyes:
 
Brown-Bomber said:
I was reading that SATA III might be made available later this year or early in 2008. If that holds true do you think we will see 15k rpm SATA drives?
Click to expand...

How does SATA with 6 Gbps signaling rates relate to 15k rpm drives? I don't even understand the need for increasing the singaling rate, since the IF speed is so much higher than the medium speed.
 
drizzt81 said:
How does SATA with 6 Gbps signaling rates relate to 15k rpm drives? I don't even understand the need for increasing the singaling rate, since the IF speed is so much higher than the medium speed.
Click to expand...


agreed.. the device must be able to perform at the interface transfer rate.
 
the 6gigs transfer is for external applications, eSata since i think you can have 4 or more drives hooked up on a SAS system that go through the one cablle
 
drizzt81 said:
I don't even understand the need for increasing the singaling rate, since the IF speed is so much higher than the medium speed.
Click to expand...

NAS/SAN setups utilizing SATA drives (like the new xServe RAID should) would benefit from the increased signaling rate.
 
sorry, what are the speeds of the Sata II and Sata III busses? (preferably in MHz, MT/s and Mb/s)
 
TeeJayHoward said:
NAS/SAN setups utilizing SATA drives (like the new xServe RAID should) would benefit from the increased signaling rate.
Click to expand...
How? Unless there's an expander or port multiplier in the middle, only one drive is talking across a single channel at once. And I haven't noticed any DAS using sata as the host bus yet... I suppose sas arrays might benefit, but they're mostly using wideports at 1.2GB/s already. For big arrays, 2.4GB/s might make a difference, but I'm skeptical that this would be useful anywhere.
MrWizard6600 said:
sorry, what are the speeds of the Sata II and Sata III busses? (preferably in MHz, MT/s and Mb/s)
Click to expand...
"Sata 2" speed is 3.0gbps. The next generation will probably bring 6.0. That's including 8/10b encoding, though - it means 300 or 600 megabytes of user data over the pipe.
 
unhappy_mage said:
How? Unless there's an expander or port multiplier in the middle, only one drive is talking across a single channel at once. And I haven't noticed any DAS using sata as the host bus yet... I suppose sas arrays might benefit, but they're mostly using wideports at 1.2GB/s already. For big arrays, 2.4GB/s might make a difference, but I'm skeptical that this would be useful anywhere.
Click to expand...
I was under the impression that all the ports on a controller were connected to a single bus. Having 4 80MB/s drives talk at the same time on a 3Gb/s bus would make the bus a bottleneck. Now, we need 8 drives in order for it to be a bottleneck... I personally have between 12 and 15 drives in my NAS at any given time. (Granted, not RAIDed, so they can't take advantage of this, but still...)
 
TeeJayHoward said:
I was under the impression that all the ports on a controller were connected to a single bus. Having 4 80MB/s drives talk at the same time on a 3Gb/s bus would make the bus a bottleneck. Now, we need 8 drives in order for it to be a bottleneck... I personally have between 12 and 15 drives in my NAS at any given time. (Granted, not RAIDed, so they can't take advantage of this, but still...)
Click to expand...

Nope. Each port is its own independent entity, independently connected to the controller at full signal rate. So having 2 raptors in raid 0 can do more than 150 MB/s at the beginning of the disk where the drives are fast enough. And on an 8-port Marvell controller I can do 180 MB/s writes, even though the drives were only sata 150. This is one of the advantages of sata over scsi - with 15 drives on a scsi chain, you get 320 MB/s total. With 15 drives on sata or sas, you can do a lot better than that.

What I was talking about with sas arrays is expanders. There, a large number of drives is aggregated and talked to over a smaller number of channels. For example, LSI makes a 28-port expander with which you could connect 24 disks to 4 sas ports. There the extra bandwidth is important - 24 disks can do more than 1.2GB/s sequential transfer (that's only 50MB/s each), so right now the 3gbps limit makes an impact on the speed of the array. You could put 20 disks on 8 ports, and the limit goes away, but that takes more controller ports.
 
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