Some questions about my first NAS project

[zantag]

Hi guys!

I am new here 'cos the time for my first freenas/truenas project has come, at last.
My plan is NAS on old cheap server platform with 5 or 6 x 6TB/8TB 3.5inch HDD in RAIDZ2. So maybe like everyone else i try to read tones of info and my head almost blow up. First big mistake was to buy Dell r710 with 32g RAM and 2x Xeon E2620 with 6x3.5 HDD slots... and PERC 6/i SAS.
Yeah thats fu*** right PERC 6/i ... so waiting almost 2 months for H200 on IT MODE and cables from ebay (-50€).

Finally i start my project with some tests HDD-s but i have some noob questions which answers i hope to find here.

1. I want to use 2 or all 4 Gbps ports on my 710 so i try link agreagation to loadbalance mode. But when i try to test the speeds ... surprise no 2Gbps+ speed. I test with iperf3 and with standart copy paste on smb share. The speed is absolutely the same 100-112MB/s with or without link agregation. Am i doing something wrong or? How to get double link speed?
2. In the middle of the motherboard of the server ( Dell r710) I find two other sata ports called SATA-A and SATA-B can i use them to attach SSD and install truenas system on it? I think this port was for CD-ROM so maybe are only SATA-3Gbps is that a problem?
3. If i get it right i have to choose CMR HDD not SMR. I find some Toshiba X300 6TB/8TB on very good price... are they CMR and good for a FREENAS project? From this list which one to choose. Are they all CMR. I read very good review for HGST so are they the best?

If not what do you suggest me to around 200€ per HDD. In my case more space is better than speed. Sorry for my noob questions and thx in advance to everyone:)

 

[jgreco]

1. I want to use 2 or all 4 Gbps ports on my 710 so i try link agreagation to loadbalance mode. But when i try to test the speeds ... surprise no 2Gbps+ speed. I test with iperf3 and with standart copy paste on smb share. The speed is absolutely the same 100-112MB/s with or without link agregation. Am i doing something wrong or? How to get double link speed?

You get more link speed by adding more clients. Please see the sticky on the topic:

https://www.truenas.com/community/threads/lacp-friend-or-foe.30541/

The ethernet standard absolutely does NOT intend for link aggregation to be used to try to improve the speed of a single connection. It is used when you are running a lot of clients on different IP's and you are filling up the capacity of a single link to your server.

 

[zantag]

My test was with two clients moving two big fails on SMB share with truenas configured to 2 ethernet ports in loadbalance mode. I expect 1 Gbps per user but the speed droped to 1/2 (50MB/s) for the two clients. Same was if i use only single ethernet port without link aggregation.

 

[jgreco]

the speed droped to 1/2 (50MB/s) for the two clients. Same was if i use only single ethernet port without link aggregation.

Yes, that can happen. If you read the LACP sticky I linked above, it explains that LACP uses hashing, so your second client has a 50/50 chance of ending up on the same port as the first. LACP on two ports really needs maybe six active clients to see good results, and isn't intended to do what you're imagining that it does. It's meant for use in a large network where there are lots of simultaneous flows, and on average that will reach nearly 2Gbps.

I expect 1 Gbps per user

Well, you need to fix your expectations. Read the sticky I linked to and adjust your worldview accordingly. Or don't. It doesn't matter to me, I'm just trying to explain the way the world actually works to you.

There is no *good* way to get what you want, which is essentially "round robin" behaviour. FreeBSD and FreeNAS supports that, but it's stupid to use it, because it will reduce performance by forcing the client to have to rearrange packets. This might even seem like it does what you want on a lightly loaded network with a fast client, but it will fall apart under load. This is why the LACP standard requires consistent flow hashing.

The way to get more speed without lots of caveats and horsing around is to upgrade to 10Gbps. We have a nice 10 Gig Networking Primer and it's worth noting that you can get a nice, well-supported 10G card and small 10G switch for just a few hundred dollars.