AFAIK, SATA HDDs are limited due to the rpm of the discs. A typical 5400 rpm HDD gives you about 100 MB/s read/write but a SATA II supports 375 MB/s read/write speed.

Assuming all the power supply issues are taken care of, can connecting multiple HDDs (spinning simultaneously as JBOD) to a single SATA port increase throughput?


Chopped up into parts:

can connecting multiple HDDs increase throughput?

Yes. RAID is usually the answer, or multiple used filesystems spread across several drives.

(spinning simultaneously as RAID JBOD)

JBOD is 'just a bunch of disks' and henbce it is not RAID.
Did you mean to write RAID or JBOD?

to a single SATA port

A single SATA port usually only connects you one device. Yopu can not connect multiple SATA drives directly to a single SATA port. There are ways around this by using a port multiplier. In case you your SATA port talks to one disk at a time. It can switch to another disk and it can do so quite fast, but it is still talking to one disk at a time and you will quickly saturate this link if you cannot 3 or more disks.

Also the motherboard (or rather the used SATA controller, which usually is part of the motherboard) needs to support this.

Is there a specific reason why you asked for one SATA port?

Traditionally one either uses faster drives, or connects multiple drives to an equal number of SATA ports. Or one usues a dedicated RAID card.

SATA II supports 375 MB/s read/write speed.

Not in practice. 270MiB/sec is about the max which is archivable on SATA-II. Note that 33.0 gigabit/second includes the bits used for protocol overhead. Actual data transfer is a lot lower. The 270MiB/sec was archieved using a fast SSD and using the SATA controller build into the ICH9/ICH10 chipsets. Other controllers usually usually slower.

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  • I meant JBOD and a Port Multiplier. Would that still talk to only one drive at a time? – Shayan Jan 15 '18 at 17:36
  • Yes, a port multiplier is a kind of switch. You ask it to connect to the disk on port 1, and then talk to the disk on port 1. When you are ready you can ask the PM to switch to the disk on port 2 and send that a command. It can switch quickly, so it seems as if you are talking to multiple drives at all. – Hennes Jan 16 '18 at 12:34
  • That does not have to be bad though. E.g., imagine ‘select disk 1’. ‘write data to disk 1’ (which probably means transfer data at wire speed to the drive’s cache). Then select disk 2, write more data [to drive cache], select disk 3, write more data to drive cache, … all at wire speed. – Hennes Jan 16 '18 at 12:34

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