2TB Barracuda Gren: 4K or not 4K that is the question.

[ClassicGOD]

Hi, I hate to ask this but my searching skills are letting me down recently ;(

Im building a new NAS Box and I'm in hardware testing stage. I'm using MSI E350IA-E45 MoBo with 8GB of DDR3 1333MHz RAM and 4 Seagate Barracuda Green 2TB ST2000DL003 drives in RAIDZ1. I'm Running FreeNAS 8.0.1 Beta 4.

They are 4K drives so in theory I should select "Force 4096 bytes sector size" right? But if I do so I get really poor performance - write speeds of about 50MBps. When I leave this option unchecked I get writes around 250MBps.

So my question is which option should I choose? Or should I wait for stable FreeNAS release?

 

[Darkaine]

For me 50MBs is fine because my network is only 100MBs (most is anyway but some areas are gigabit), so really its up to you and how you use your NAS. Mine is there only for streaming files and such (that I've already backed up elsewhere) without having to search through several stacks of discs.

 

[ClassicGOD]

Yes but my network is gigabit and I'm all about performance ;) I will destroy and create new RAIDZ once stable 8.0.1 comes out and will repeat the test to check if anything changes. I was just wondering if anyone knows why I'm getting counterintuitive results.

 

[Darkaine]

Lol, alright, as for the speeds and such I can't answer the why, I just was answering the "Which option I should choose" question.

 

[matthewowen01]

As far as i know, there is no real benefit of 4k sectors currently. In the future performance will be increased but not yet, it's in the 'get it adopted stage.'

 

[Darkaine]

ah, makes sense. Any clue when it will be in the "this really works" stage? (just curious)

 

[matthewowen01]

i don't really know, i hope soon, but there should not have a performance degradation though. My guess is they are not being aligned properly but i don't know enough to tell you how to check.

 

[knightwolf]

I don't think I ticked the box to force this ... how would I check if my pool is set to 4k?

 

[b0bje]

zdb | grep ashift

if it returns 12 you're good. (9 means you're on 512byte blocks)