So whats up in SCSI land these days?

[cv643d]

I am currently brainstorming about possible configuration alternatives for my new workstation replacing my aging 2.4 P4 system with 512 MB and 320GB harddrive.

It looks like Im going for QuadCore Intel CPU and 4 GB memory. Then I started to look at fast harddrives thinking they would improve loading of programs and such. So the Raptor is at 10k rpm, but SAS drives are at 15k rpm, they are quite expensive but if they are even faster than SATA Raptors one SAS drive for system and apps might just be worth it.

So what kind of SAS card is recomended?
Is it hard to set up with Vista?
I remember old SCSI took a bit longer to boot than regular IDE, is it the same with SAS?
Is it really worth it in comparison with the latest Raptor? I hate a sluggish system and want instant response from the system when I work with multiple applications.

Thanks!

 

[longblock454]

In general, SCSI is on the way out IMO, those cables suck! Seagate will be releasing SATA drives with the SAS interface built in, no more little converter cards!

But currently no 15K SATA drives are available, won't be long if you ask me!

 

[cv643d]

As I understood it with SCSI the system did never halt beacause of disk operations because the SCSI drive had its own CPU and did not need the computer CPU for that.

How is it with modern SATA drives?

 

[longblock454]

The SCSI standard is old, really old! I don't know all the details, but the fastest is only 640Mbps, SATA is up to 3Gbps!

 

[-Sean Casey]

SAS is not limited to the same restrictions of SCSI.... And is very fast (up to 6 gb/s iirc).

For a typical system SATA is fast enough, but if you want to run a monter RAID array then 15k RPM SAS drives will prove very fast. SATA drives can be connected to a SAS backplane, but SAS drives can not be connected to SATA backplane.

SAS and SATA are much more similar to each other then PATA and SCSI are.

 

[DanNeely]

The SCSI standard is like the ATA standard. Both date back a few decades and have gone through multiple implementations since. I wouldn't get a parallel scsi drive (any flavor) any more than a pata drive these days, but for bleeding edge high end systems a SAS (Serial Attached Scsi) drive will outperform a Sata drive.

 

[drizzt81]

Wow, there is a lot of misinformation in this thread.

Parallel SCSI went up to 320MB/s (not Megabits, but MegaBYTES), which is still a bit faster than the 300MB/s offered by the current SATA standard. However, we all know that the interface speed matters little in HDD land, since drives are generally much slower than either of these specs.

Anyway, the SCSI equivalent to SATA is called SAS and has some nifty features, such as allowing you to run regular SATA drives on a SAS bus. I am not sure about the exact differences between the interface, but I heard of dual-ported SAS drives, so maybe daisy-chaining works with SAS? I am sure that the inquiring mind can find a nice wikipedia article outlining what SAS can or cannot do.

On to the drives:
If you believe storagereview, then there is little reason to get a 15k rpm SAS drive for home usage. Raptors are cheaper and in most instances faster for single user access patterns. SAS drives are likely a smart investment for server type loads, say running a SQL database with lots of queries or having a bunch of VMs stored on the same HDD.

On to 15K rpm SATA drives:
given the rapid descent in price of solid-state drives and their vastly superior access times, I am willing to bet $20 that there will not be any 15k rpm SATA drives. There is no market for them.

 

[Tangent inc.]

Wow, there is a lot of misinformation in this thread.

Parallel SCSI went up to 320MB/s (not Megabits, but MegaBYTES), which is still a bit faster than the 300MB/s offered by the current SATA standard. However, we all know that the interface speed matters little in HDD land, since drives are generally much slower than either of these specs.

Anyway, the SCSI equivalent to SATA is called SAS and has some nifty features, such as allowing you to run regular SATA drives on a SAS bus. I am not sure about the exact differences between the interface, but I heard of dual-ported SAS drives, so maybe daisy-chaining works with SAS? I am sure that the inquiring mind can find a nice wikipedia article outlining what SAS can or cannot do.

On to the drives:
If you believe storagereview, then there is little reason to get a 15k rpm SAS drive for home usage. Raptors are cheaper and in most instances faster for single user access patterns. SAS drives are likely a smart investment for server type loads, say running a SQL database with lots of queries or having a bunch of VMs stored on the same HDD.

On to 15K rpm SATA drives:
given the rapid descent in price of solid-state drives and their vastly superior access times, I am willing to bet $20 that there will not be any 15k rpm SATA drives. There is no market for them.

i feel the same way. platter based storage seems like it will cover the high capacity market for some time and SSD may phase high spindle speed drives out. i don't know about robustness because flash has maximum write cycles but platter based drives exhibit mechanical failure.

 

[OmegaAvenger]

i feel the same way. platter based storage seems like it will cover the high capacity market for some time and SSD may phase high spindle speed drives out. i don't know about robustness because flash has maximum write cycles but platter based drives exhibit mechanical failure.

True, but with platter drives, as long as the head doesnt dig into the drive, if it fails you're data is still there and can be retrieved (albeit its expensive). If SSD drives fail similar to some USB flash drives, you're data is gone.

 

[drizzt81]

True, but with platter drives, as long as the head doesnt dig into the drive, if it fails you're data is still there and can be retrieved (albeit its expensive). If SSD drives fail similar to some USB flash drives, you're data is gone.

Would you mind elaborating this a bit more? How would a flash drive lose data more easily when compared to a platter based drive, if neither are physically damaged?

 

[Zardoz]

Wow, there is a lot of misinformation in this thread.

Parallel SCSI went up to 320MB/s (not Megabits, but MegaBYTES), which is still a bit faster than the 300MB/s offered by the current SATA standard. However, we all know that the interface speed matters little in HDD land, since drives are generally much slower than either of these specs.

Anyway, the SCSI equivalent to SATA is called SAS and has some nifty features, such as allowing you to run regular SATA drives on a SAS bus. I am not sure about the exact differences between the interface, but I heard of dual-ported SAS drives, so maybe daisy-chaining works with SAS? I am sure that the inquiring mind can find a nice wikipedia article outlining what SAS can or cannot do.

On to the drives:
If you believe storagereview, then there is little reason to get a 15k rpm SAS drive for home usage. Raptors are cheaper and in most instances faster for single user access patterns. SAS drives are likely a smart investment for server type loads, say running a SQL database with lots of queries or having a bunch of VMs stored on the same HDD.

On to 15K rpm SATA drives:
given the rapid descent in price of solid-state drives and their vastly superior access times, I am willing to bet $20 that there will not be any 15k rpm SATA drives. There is no market for them.

Just to add to the SAS granted that it's only 300MB/s but SAS is also Full Duplex to where Ultra 320 is not. this also can make a big different s in performance. older scsi used to be full duplex, but lost it in ultra 320, and IMO was a big loss even though the speed was better.

Also SAS is a point to point connection so each device gets 300MB/s PSCSI was 320MB/s for the whole bus chain. All in All SAS is much better then any older SCSI with it's 300MB/s per device in full duplex, adding a crap ton of devices with extenders. at is also better to SATA as SATA is only half duplex and the drives are somewhat slower due to the target market.

 

[Tangent inc.]

True, but with platter drives, as long as the head doesnt dig into the drive, if it fails you're data is still there and can be retrieved (albeit its expensive). If SSD drives fail similar to some USB flash drives, you're data is gone.

flash is nearly permanent unless overwritten. the cells either hold a bit or they don't. if you apply an ESD to the cell it will be damaged but that is physical.

you may be thinking about a flash drive being corrupted. in this case you don't have access to the data but it is indeed still there. widows forces you to format a flash drive it does not recognized as containing data resulting in a voluntarily deletion of the the data yourself. of course only if you wish to use the drive in its limbo state. you can very well send a flash drive out to be recovered as any platter based storage... if you wallet permits.

 

[Tangent inc.]

Just to add to the SAS granted that it's only 300MB/s but SAS is also Full Duplex to where Ultra 320 is not. this also can make a big different s in performance. older scsi used to be full duplex, but lost it in ultra 320, and IMO was a big loss even though the speed was better.

Also SAS is a point to point connection so each device gets 300MB/s PSCSI was 320MB/s for the whole bus chain. All in All SAS is much better then any older SCSI with it's 300MB/s per device in full duplex, adding a crap ton of devices with extenders. at is also better to SATA as SATA is only half duplex and the drives are somewhat slower due to the target market.

is it the sata bus that is half duplex or the drive controller... or both. i am asking because i am picking up a SAS 16 channel raid controller to use with 15 1tb drives. is the sata controller going to drop the sas bus to half duplex?

the intigrated sas port sounds interesting.

 

[Zardoz]

is it the sata bus that is half duplex or the drive controller... or both. i am asking because i am picking up a SAS 16 channel raid controller to use with 15 1tb drives. is the sata controller going to drop the sas bus to half duplex?

the intigrated sas port sounds interesting.

It's the drive and controller. No it will not, you can run SAS and SATA and will not effect the speed of each other remember this is a point to point connection so the do not share the same data bus as like parallel. this is also why you cant RAID SAS and SATA together. but you can have one SAS RAID and one SATA RAID.

 

[AreEss]

Just to add to the SAS granted that it's only 300MB/s but SAS is also Full Duplex to where Ultra 320 is not. this also can make a big different s in performance. older scsi used to be full duplex, but lost it in ultra 320, and IMO was a big loss even though the speed was better.

Fine. I'll go get my FC-AL drives. Yes, FC-AL at the drive itself, with large cache. 2GB/sec - that's gigaBYTE - burstable. Also, please, call me when your SATA drives can get anywhere near 180MB/sec sustained random in 4MB chunks for 40GB pulling >10K IOPS. Hint; never ever, period.

Also SAS is a point to point connection so each device gets 300MB/s PSCSI was 320MB/s for the whole bus chain. All in All SAS is much better then any older SCSI with it's 300MB/s per device in full duplex, adding a crap ton of devices with extenders. at is also better to SATA as SATA is only half duplex and the drives are somewhat slower due to the target market.

SATA/SAS is SERIAL! Did you fail basic acronyms or something? SERIAL ATA, SERIAL Attach SCSI. Secondly, Serial's been around for ages. There's serial FC and IBM SSA. Both of which are full duplex just like current SC/LC FC. And what is wrong with you people? Dual ported SAS is the same as dual ported FC - the second port is for path redundancy, not speed! Not everything is about how fast you can hump the platters into dust!

 

[Zardoz]

Fine. I'll go get my FC-AL drives. Yes, FC-AL at the drive itself, with large cache. 2GB/sec - that's gigaBYTE - burstable. Also, please, call me when your SATA drives can get anywhere near 180MB/sec sustained random in 4MB chunks for 40GB pulling >10K IOPS. Hint; never ever, period.



SATA/SAS is SERIAL! Did you fail basic acronyms or something? SERIAL ATA, SERIAL Attach SCSI. Secondly, Serial's been around for ages. There's serial FC and IBM SSA. Both of which are full duplex just like current SC/LC FC. And what is wrong with you people? Dual ported SAS is the same as dual ported FC - the second port is for path redundancy, not speed! Not everything is about how fast you can hump the platters into dust!

huh, yeah SAS and SATA are serial what about it? still a point to point connection. this means that drives do not share the same data cable, I am not pointing out that Serial FS and IBM SSA is not full duplex I am pointing out that SAS is full duplex and SATA is not, I dont know where FC and SSA SC/LC FC came in to play on this as we are not talking about them.

anyways you are reading to far into this, way far...

 

[OmegaAvenger]

Would you mind elaborating this a bit more? How would a flash drive lose data more easily when compared to a platter based drive, if neither are physically damaged?

flash is nearly permanent unless overwritten. the cells either hold a bit or they don't. if you apply an ESD to the cell it will be damaged but that is physical.

you may be thinking about a flash drive being corrupted. in this case you don't have access to the data but it is indeed still there. widows forces you to format a flash drive it does not recognized as containing data resulting in a voluntarily deletion of the the data yourself. of course only if you wish to use the drive in its limbo state. you can very well send a flash drive out to be recovered as any platter based storage... if you wallet permits.

Yeah, thats what I was reffering to. But with platter drives, you could merely move the platters to an identical model drive if its just controller board/server/spindle motor thats bad. with flash chips unless you are damned good as soldering, thats not likely to be the case. And BGA would make it that much harder.

Fine. I'll go get my FC-AL drives. Yes, FC-AL at the drive itself, with large cache. 2GB/sec - that's gigaBYTE - burstable. Also, please, call me when your SATA drives can get anywhere near 180MB/sec sustained random in 4MB chunks for 40GB pulling >10K IOPS. Hint; never ever, period.



SATA/SAS is SERIAL! Did you fail basic acronyms or something? SERIAL ATA, SERIAL Attach SCSI. Secondly, Serial's been around for ages. There's serial FC and IBM SSA. Both of which are full duplex just like current SC/LC FC. And what is wrong with you people? Dual ported SAS is the same as dual ported FC - the second port is for path redundancy, not speed! Not everything is about how fast you can hump the platters into dust!

I've got some FC-AL drives too. fun stuff.

 

[drizzt81]

Yeah, thats what I was reffering to. But with platter drives, you could merely move the platters to an identical model drive if its just controller board/server/spindle motor thats bad. with flash chips unless you are damned good as soldering, thats not likely to be the case. And BGA would make it that much harder.

Yes, but that is a limitation inherent in using the Windows OS, not something inherent in flash drives. If you can use `dd' to grab the bits off the device, then you could analyze it and recover your data at home. A broken PCB on a HDD is also a physically damaged drive. It may be possible to transplant a flash chip onto an equivalent PCB in case of such damage. Of course, that is more complex than swapping a HDD's PCB, since it requires soldering.

 

[Tangent inc.]

It's the drive and controller. No it will not, you can run SAS and SATA and will not effect the speed of each other remember this is a point to point connection so the do not share the same data bus as like parallel. this is also why you cant RAID SAS and SATA together. but you can have one SAS RAID and one SATA RAID.

thanks... i was just not aware that sas and sata drives would mesh on a single controller. i guess ill read up on the switches and stuff.

this is a nice breakdown of info... minus the flaming.

 

[Zardoz]

Check with the controller if it will do both, but what I have seen most do.