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I have four 2 TB SATA II drives that I intend to connect to an LSI 8888ELP card. The card has two Mini SAS ports, and I am going to connect the drives with an SFF 8087 to 4x SATA breakout cable. But the part I am confused on is the specs of the card say "3.0 Gbps per port." Does this mean there's a total of 3 Gbps per SAS connector on the card (of which there are two), or 3 Gbps per SATA port when using the breakout cable? Additionally, would there be any benefit from connecting two SATA drives to one SAS port and two to the other, or simply connecting all four drives to the same SAS port with a single breakout cable? I am going to put the four drives in a RAID 5 array.

WaxTrax
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2 Answers2

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Does this mean there's a total of 3 Gbps per SAS connector

Yes and no. What you are calling the 'SAS connector' should be seen as 'FOUR ports`, not as one. Each of those is capable of 3.0Gbps.

This means you can connect four drives with a breakout cable and each drive will be connected at 3.0Gbps. Or if you use two breakout cables you can connect up to 8 drives, each at 3.0 Gbps.

would there be any benefit from connecting two SATA drives to one SAS connector and two to the other, or simply connecting all four drives to the same SAS port

I would use a single breakout cable to keep it the number of cables down, but other than that is does not really matter.

Make sure you read this post and make sure that you understand that RAID is not a form of backup.

URE can (and sometimes will) happen during a rebuild. Fire and theft will still take out all drives. RAID in this form simply means you do not have to worry about down-time when a single disk fails and allow you to make a quick backup if your last backup was old.

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Hennes
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  • Thanks for the info :-) Regarding backups, all of the data will be backed up with a cloud service. – WaxTrax Dec 31 '13 at 16:17
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Sometimes it just pays to read the manual :-)

"The SAS RAID controllers integrate eight high-performance SAS/SATA II PHYs and a PCI Express bus master DMA core. Each of the eight PHYs is capable of 3.0 Gbit/s SAS link rates and 3.0 Gbit/s SATA II link rates."

This single paragraph answers all of my questions.

WaxTrax
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