New News. AOC-SAT2-MV8. Supports Port Multipliers.

Not sure if anyone knew this, but I just discovered a little while ago the driver for the Supermicro AOC-SAT2-MV8 supports port multipliers.

I had a suspicion it would after testing the Rosewill RC-218 which has a Marvel Chip and supports Port Multipliers.

So after assembling my new expanded unRAID X7SBE * 2 AOC-SAT2-MV8,s I externalized one of the ports and connected a 5 port array to it.

lo and behold it worked. Granted it was only 500GB drives in that chassis.

I got a clean 60MB/s on the drives, and even with two drives accessed simultaneously.

I have not gone further with it as my new expanded array is full.

When unraid can support 24 or more drives, I'll experiment with it further.

It does open up the possibility of 40 drive arrays with the right hardware.

Not sure how practical it is, but it's possible!

Anyone get to test the AOC-SASLP-MV8 with port multipliers?

i currently have 2 of the aoc-sat2-mv8 cards in my norco 4020, but my case is full right now. how many ports are you talking about? does each slot become 2? or 5? what is the potential limit to these cards? will they become saturated at a point that is unrealistic?

how many ports are you talking about? does each slot become 2? or 5?

Each slot can become 2 or 4 or 5 depending on the port multiplier you purchase.

But there is a cost associated with each hardware piece. See addonics.com for ideas.

what is the potential limit to these cards? will they become saturated at a point that is unrealistic?

I do not know. Each port is theoretically capable of 5 ports so 8 x 5.

Motherboard bandwidth can be an issue, plus there is command based switching and FIS switching.

One has latency, the other allows simultaneous commands.

I think the bandwidth limit per drive is 60MB/s. Even if the drive is capable of more, that's all you will get.

However with the right controller and multiplier, that is 60MB/s simultaneous to each of 5 drives.

I think this works out good for RAID5, I'm not sure about unRAID.

For reading it should be fine. When you do a parity check that's where the lag may result.

I would surmise that rotating or doing a round robin technique of assigning the drives vs controller vs multipliers would help alleviate bandwidth bottlenecks.

If backblaze can do 5 drives per multiplier per PCI slot (not even PCI-X but PCI) I'm sure it can be done in unRAID.

The only issue at this time is unRAID supports up to 20 drives.

Going beyond that requires limetech to increase maximum drives.

At some point it just makes sense to have multiple servers.

Port multipliers seem to cost as much per port as the controller....

They have downsides, but you can purchase external 4 & 5 drive removable units that have the port multiplers built in.

Besides, when you run out of controller slots, it provides a way of expanding without a total redesign.

I realize that this is an old thread, but I'm hoping that people have become less cynical of port multipliers...

Has anyone discovered any options for multiplying ports on  AOC-SASLP-MV8 card or a X7SPA-HF?

I realize that this is an old thread, but I'm hoping that people have become less cynical of port multipliers...

 

Has anyone discovered any options for multiplying ports on  AOC-SASLP-MV8 card or a X7SPA-HF?

The saslp-mv8 will support a SAS expanders.

In theroy you could put up to 32 drives on a single SASLP-MV8, but you parity checks would be slow.

the INT13 bios will only see 8 drives. but the OS will see all the drives.

more then once i have considered building a 22 drive unraid server with just an X7SPA, HBA and an expander. 16 on the Expander and 6 on the mobo.

just be warned that after 6 drives, the SASLP is already saturated. the more drives you add. the slower parity will become.

the X7SPA is an intel ICH9 in theory it will support port multiplier, but I have not tested it so...

again, 5 drives on a single port would be slow also.

I realize that this is an old thread, but I'm hoping that people have become less cynical of port multipliers...

 

Has anyone discovered any options for multiplying ports on  AOC-SASLP-MV8 card or a X7SPA-HF?

 

The saslp-mv8 will support a SAS expanders.

In theroy you could put up to 32 drives on a single SASLP-MV8, but you parity checks would be slow.

the INT13 bios will only see 8 drives. but the OS will see all the drives.

 

more then once i have considered building a 22 drive unraid server with just an X7SPA, HBA and an expander. 16 on the Expander and 6 on the mobo.

just be warned that after 6 drives, the SASLP is already saturated. the more drives you add. the slower parity will become.

 

 

the X7SPA is an intel ICH9 in theory it will support port multiplier, but I have not tested it so...

again, 5 drives on a single port would be slow also.

I would think the SAS expander would handle the multiple drives better then a SATA Port Multiplier.

SAS comes from SCSI and SCSI hands multiple devices on a bus much better then Serial ATA.

SCSI has always had the ability to handle multiple devices, send commands disconnect and get an update from the device in sync with the bus.

Whereis with serial ATA communication is always point to point. With a multiplier. the communication is multiplexed, With ( i  believe) command based switching there is a bottleneck Throughput ends up being 60MB/s.

It would be interesting to see how the SAS expanders compare to the SATA port multipliers.

The sas expander will do better then a port multiplier.

the bottleneck is the SASlp-mv8 is a PCIe 4x card. it would work though.

The SASLP-MV8 does not officially support expanders, people on Hard experimented and  they worked.