Mac Mini Server Link aggregation - Thunderbolt or USB 3 gigabit ethernet adaptors

[gavcooper]

I am setting up a late 2012 Mac Mini as a file server with Server 2.2. It has a Promise Pegasus R4 RAID and LaCie 4TB drives daisy chained via the thunderbolt connection. 4 users on MacPro's will connect to the server to access these hard drives via gigabit ethernet.

I imagine the gigabit ethernet will be the bottleneck, so I'm now looking at link aggregation. Not a problem on the MacPro's but the Mac Mini will require an adaptor to get a second gigabit port. From reading this forum I understand the Apple Thunderbolt to Gigabit adaptor will work, but I'm concerned that it will need to be fitted 3rd in line after the R4 and LaCie drives. The 10Gbps bandwidth Thunderbolt has, may cause another bottleneck with all three working off the same port?

An option would be to use one of the USB 3 ports with this adaptor http://www.ebuyer.com/412005-startec...edium=products
I believe it work with OSX, but I have no speed information or if OSX link aggregation will work using it.

Any thoughts on the above would be appreciated and recommendations on a suitable Network Switch with LACP support welcome.

[hchung]

Originally Posted by gavcooper

I am setting up a late 2012 Mac Mini as a file server with Server 2.2. It has a Promise Pegasus R4 RAID and LaCie 4TB drives daisy chained via the thunderbolt connection. 4 users on MacPro's will connect to the server to access these hard drives via gigabit ethernet.

I imagine the gigabit ethernet will be the bottleneck, so I'm now looking at link aggregation. Not a problem on the MacPro's but the Mac Mini will require an adaptor to get a second gigabit port. From reading this forum I understand the Apple Thunderbolt to Gigabit adaptor will work, but I'm concerned that it will need to be fitted 3rd in line after the R4 and LaCie drives. The 10Gbps bandwidth Thunderbolt has, may cause another bottleneck with all three working off the same port?

An option would be to use one of the USB 3 ports with this adaptor http://www.ebuyer.com/412005-startec...edium=products
I believe it work with OSX, but I have no speed information or if OSX link aggregation will work using it.

Any thoughts on the above would be appreciated and recommendations on a suitable Network Switch with LACP support welcome.

I've never used link aggregation before, but it'll work with any adapter as long as the adapter works because it's independent of the adapter driver.

That said, it probably doesn't matter too much whether you pick the USB or TB gigabit adapter because two gigE ports won't be able to pull enough data off the TB drives to hit a bottleneck on TB. Your bottleneck is still the network.

[gavcooper]

Thank for the reply, hchung

The safest option would be the Apple Thunderbolt GigE adaptor as the drivers are probably built into OSX. The StarTech USB 3 adaptor would require its own driver which could cause problems.

Without trying it I can't see if two external RAID hard drives + the GigE adaptor will experience a performance issue.

Can anyone advise on the best way to measure the speed of a network? So I can see if LACP improves on our current single gigabit connection.

[ytk]

Generate a 1GB file of random data with

dd if=/dev/random of=bigfile bs=1048576 count=1024

Then see how long it takes to copy it over the network with each type of connection:

time cp bigfile /path/to/network/share

[gavcooper]

Thanks ytk, I have tested current single gigE connection to the Pegasus Thunderbolt RAID connected to the Mac Mini Server.

These are the figures:

real 0m11.212s
user 0m0.002s
sys 0m3.924s

Not sure if these are good figures for a gigabit connection, and if LACP will improve on this. Looks to me just under 100Mb/s, would that be correct for a 1000Mb/s connection?

[Umac-de]

Originally Posted by gavcooper

Not sure if these are good figures for a gigabit connection, and if LACP will improve on this. Looks to me just under 100Mb/s, would that be correct for a 1000Mb/s connection?

You only have a 1GBit/s connection, not 1 GB/s
So 1000 GBit / 8 = 125 MB (theoretical max)

And LACP cannot improve on this, because LACP can only user based load balancing (not data based)

[Umac-de]

We have had a test on this with 3 MacPro:

Test 1
2x 6,95 GB files -> Server -> Bond(en0) -> Switch -> GigaBit -> MacPro1
13,9 GB in 2:06 = ca. 113MB/s

Test 2
2x 6,95 GB files -> Server -> Bond(en1) -> Switch -> Bond -> MacPro2
13,9 GB in 2:09 = ca. 110MB/s

Test 3 (at the same time)
6,95 GB file -> Server -> Bond(en0) -> Switch -> GigaBit -> MacPro1
6,95 GB file -> Server -> Bond(en1) -> Switch -> Bond -> MacPro2
13,9 GB in 1:19 = ca. 174MB/s

LACP works connection/user based - no improvement in test 2

[gavcooper]

Originally Posted by Umac-de

You only have a 1GBit/s connection, not 1 GB/s
So 1000 GBit / 8 = 125 MB (theoretical max)

And LACP cannot improve on this, because LACP can only user based load balancing (not data based)

I will have 4 users accessing the server at the same time, file sharing off the Pegasus RAID.

[Umac-de]

Originally Posted by gavcooper

I will have 4 users accessing the server at the same time, file sharing off the Pegasus RAID.

Ok, then you will have 2 on one ethernet port an 2 on the other of the server...
You only need a bond connection from the server to your switch and LACP activated on the switch with round-robin
(else it is only fall back).
But:
It is connection based and the connection is as it happens, random and fixed!
So:
User A on en0, user B on en0,
user C on en1, user D on en1.

If only A + B are pulling files from the server, none of them can use en1!

[gavcooper]

Okay, thanks for your replies

[Umac-de]

Originally Posted by gavcooper

Any thoughts on the above would be appreciated and recommendations on a suitable Network Switch with LACP support welcome.

For 5:
Netgear GS108T-200

[mus0r]

For what it's worth, I have yet to have a compatibility problem with USB to ethernet dongles on Mac. Of the 3 or 4 I've tried on my own and others' Macs, they all worked and only one required me to find a driver.

Had the same results with eSATA cards on my Mac Pro. I think people sell Apple short in terms on hardware compatibility.