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which one is better? SAS/FC/SATA/SCSI

Which technologies has a better performance in a SAN box?
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caspco
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caspco
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4 Solutions
 
wolfcamelCommented:
depends on so many factors..
sas and fibre channel would typically give overall best performance.
but to truely compare - it will often depend on the type of data and quantity -
eg small files being written, large files being written, or lots of small reads, or large contiguous reads.
what sort of RAID you configure can also make a difference.
However in general - if you assume an identical physical drive with just a different controller interface then FC/SAS/SCSI/SATA would be my general order of performance.

Hoewever if you through cost effectiveness into the equation it is hard to beat a large SATA raid for performance vs cost
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Neil RussellTechnical Development LeadCommented:
It is generally accepted that in the Enterprise, where you would expect to find a SAN, that the san uses SAS drives but is then connected on a FC connection to your server hosts.

A good SAN will have dual FC ports and DUAL NIC ports for crossover failure and redundancy.
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irweazelwallisCommented:
Fibre Channel will always be quickest.
You can get some awesome performance out of JBOD's - but sacrifice the redundancy that you get from a SAN.
Don't forget to apply the normal ideas of performance - more spindles = quicker volumes
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AhmedHERMICommented:
Hello ;

There's not that much difference between the drive technologies.

FC at 4Gbps is going to prove marginaly faster in the average SAN storage array than a 3.2Gbps SAS drive. So use more SAS drives in RAID-10 instead of your FC drives in RAID-5 and enjoy higher performance and lower cost.

Another point worth considering: how many spindles are on the bus or loop? Nine 15K RPM spindles on an Ultra320 SCSI bus won't out-perform nine 15K RPM 4Gb FC spindles, but they will outperform, say, two shelves worth of 15K RPM 4Gb FC spindles attached to the same FCAL. If those same FC drives are Dual-Ported, there will be an additional penalty in contention from two active storage processors.

If you're the typical shop (meaning, if you're implementing server virtualization because most of your servers aren't that I/O or CPU intensive), then you should probably concern yourself more with how much cache your SAN storage processor has and worry less about FC vs. U320.

in this link you can find a comparison between different drives technologies
http://www.webopedia.com/DidYouKnow/Computer_Science/2007/sas_sata.asp

Hope it helps you.
Regards.
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Martin_J_ParkerCommented:
These days I think you can remove SCSI from the equation.  SAS or Serial Attached SCSI is newer, at least as quick, often cheaper and has effectively replaced the old SCSI.  See http://en.wikipedia.org/wiki/Serial_attached_SCSI for some technical detail.

If you care at all about performance and can afford SAS I'd certainly recommend it over SATA.
Fibre Channel is going to cost you a lot more, so you'll need good justification for that.
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AhmedHERMICommented:
Like Martin J Parker said:
for SCSI you can remove the equation, it's not supported any more.
there's a very interesting Technology used nowadays, iSCSI, it's Cheaper even Free with Microsoft Windows Server and it's included with new Storages.
Check this link Plz : http://searchstorage.techtarget.com/definition/iSCSI 

Let US know :)
Regards
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Neil RussellTechnical Development LeadCommented:
iSCSI is NOT a drive technology it is a transfer protocol for presenting data storage to a device.
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AhmedHERMICommented:
Well i think the Question is not only about Drives :)
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Martin_J_ParkerCommented:
I've seen iSCSI implemented over SAS and SATA - iSCSI refers to the SCSI command set passed over the IP network protocol and has little to do with the type of physical device connected. If you're looking at iSCSI I would still recommend SAS over SATA, although you can certainly get some cheap iSCSI SATA devices from Thecus.
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kevinhsiehCommented:
FC drives themselves are also being replaced by SAS as a drive controller technology. In a modern SAN, the drive options are really just SAS or SATA, and the most modern SANs are using 7.2K nearline SAS instead of 7.2K SATA drives. A SAS drive will generally perform better than SATA, even at the same RPM for random workloads.

That said, a SATA SSD will smoke any 15K FC/SAS/SCSI drive...
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Martin_J_ParkerCommented:
Yes, if you want really fast look at SATA SSD.  Another option - if you can afford it - is to use a tiered approach which uses both SSD and SAS: http://www.infoworld.com/d/storage/infoworld-review-dell-iscsi-san-sizzles-ssd-dynamic-storage-tiering-625?page=0,0
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irweazelwallisCommented:
SSD's are not reliable or large enough to provide a reliable storage medium as yet.

Fibre Channel you can get reliance on the networking side of it with dual fibre switches and opens up the possibilities of storage replication at an enterprise level.

16GB fibre channel is nearly here or Fibre channel over ethernet either way you#ll get some very fast kit
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Martin_J_ParkerCommented:
I think that's the whole point of the tiered approach - use smaller SSDs to get the speed, RAID it to improve reliability, fall-back to SAS RAID for the bulk of the storage, which will still be reasonably quick.  Check out that infoworld.com link above - it's interesting technology.
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andyalderSaggar makers bottom knockerCommented:
Little bird told me they were giving up on making FC interface drives since SAS interface is just as good as FC and it costs more to make two separate interfaces. Take a look at Seagate Cheetah for example, no 8Gb FC variant, only 4Gb but 6Gb SAS.
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kevinhsiehCommented:
@Andy: yup, I already mentioned that. I think that we can consider both FC and SCSI as legacy drive interfaces. Everything going forward is SAS and SATA.
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Gerald ConnollyCommented:
I think this discussion has brought out an interesting point in that newcomers into the storage field still think of disks in terms of the interface only as shown by the OP, whereas those of us who have been doing it for a while think of the disk interface as an edge technology, completely seperate from the interconnect/SAN technology.

Disk interfaces: SCSI/SATA/SAS/FC  (there are a more but this set cover the majority of disks most people come across today, and some of these are now deprecated e.g SCSI (& FC?))

SAN interconnects: FC/SAS/iSCSI/Infiniband/etc  

Disk technology: Spinning disk/SSD
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caspcoAuthor Commented:
@AhmedHERMI:

Nowadays, most SAS drives are dual port, thus their speed has been increased to 6 Gb.
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andyalderSaggar makers bottom knockerCommented:
Not really; nowadays most SAS disks have two 6Gb ports, however not that many controllers use both ports and the second port is often reserved for a second controller for redundancy, especially when used in SAN attached storage.
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