Any thought about the Seagate Archive HDDs?

[AndreStarTrek]

The question is easy, any thought about the Seagate Archive HDDs?

http://www.seagate.com/nl/nl/products/enterprise-servers-storage/nearline-storage/archive-hdd/

I am thinking of running 8x 8TB Seagate Archive drives in Z3.

 

[Ericloewe]

The possibilities range from ZFS being the perfect file system for these drives to ZFS being a third layer of possible fragmentation on top of the traditional sequential sectors and the SSD-like shingles.

If ZFS can be tuned to use blocks that are integer multiples of the shingle size and assuming proper alignment, ZFS really is perfect for these drives.

Don't ask me how you're supposed to find out the shingles' size, because I have no idea beyond "trial and error".

tl;dr
Count on crummy performance for random workloads and/or the "thrill" of being an early adopter and associated troubleshooting.

 

[zambanini]

it depends what you want to store. as long as you do not overwrite files, smr sounds interesting. I would only use it as second backup archive, since the first test drives were horibly slow on writes( non zfs)

 

[AndreStarTrek]

What kind of write speed should I expect with my described HDD setup?

 

[jgreco]

Unknown. However, if you're using ZFS and maintain a fair bit of free space, it will probably be better than an average file system's speed because ZFS tends to lay down contiguous data where possible.

 

[zambanini]

keep in mind that these drives are for archiving. write once..read from time to time. see them as tape drives scnr. if a freed sector gets rewritten, the inner and outer tracks (not sectors) will be written completly, since they overlap http://www.hgst.com/sites/default/files/images/science-of-storage/SMR_visual.jpg.

 

[jgreco]

keep in mind that these drives are for archiving. write once..read from time to time. see them as tape drives scnr. if a freed sector gets rewritten, the inner and outer sector will be written completly, since they overlap http://www.hgst.com/sites/default/files/images/science-of-storage/SMR_visual.jpg.

Which is really where HDD based storage seems to be headed, something I've been saying for several years now.

The "enterprise class" high speed hard drives have endurance and little else going for them, at ridiculous prices for what is still spinny rust, and you get to choose between fast drive or high capacity.

SSD tech is gaining rapidly in endurance and are not totally out of line pricewise compared to enterprise class hard drives, though SAS SSD's are still priced rather ridiculously. But a SSD will typically outclass an enterprise class HDD on IOPS except possibly for sequential.

Cheap SATA platters have always been a ZFS strength, and ZFS has the ARC and L2ARC to help mitigate some of the performance issues. ZFS also sports the larger block sizes that I'm guessing would help out substantially with some of the write performance issues of the shingled stuff, but of course that's just an uneducated guess.

So I've not been too shocked to see hard drives shying away from the 15K and 10K RPM variants; they no longer make as much sense in this era of SSD, and the big drives are 5400 or 5900RPM in most cases. We have some middle ground at least for a little while in the form of small capacity high performance hard drives for applications where SSD's are not going to cut it just yet, but some of the latest SSD's are rated for 10 writes per day and that's getting close to covering what even a very busy HDD might be required to do.

 

[AndreStarTrek]

keep in mind that these drives are for archiving. write once..read from time to time. see them as tape drives scnr. if a freed sector gets rewritten, the inner and outer tracks (not sectors) will be written completly, since they overlap http://www.hgst.com/sites/default/files/images/science-of-storage/SMR_visual.jpg.

Yes i did read about the working of this drive.

I will mainly use is for storage. But I would like to replace my desktop hdd with a iscsi over dual nic and i like to use NFS. I also will use freenas for bittorent download and let it download on a mirror SSD that would make the HDD idle more and in that case i think putting the ZIL and L2ARC on the mirror SSD would make sense.

I have read a lot about freenas, but I don't have a production system yet.

As for now, I have the following hardware already.

Supermicro X10SL7-F
Pentium G3440 3.3Ghz
2x8GB total 16GB ECC Unbuffered http://www.crucial.com/usa/en/ct102472bd160b (wil upgrade in the future to 32GB total)
2x Intel 320 40GB SSD mirror install for freenas

Want to buy
2x 250GB +/- SSD in mirror for torrent download and ZIL and L2ARC
8x 8GB Seagate Archive HDDs

Maybe this make it more doable to make a estimate how fast the Write, but also the Read speed could be. Or at least what could i expect wen i use normal 4TB disks.

 

[zambanini]

for l2arc plan at least 64gb ram. btw do not slice the ssd, it makes things slow ( so do not mix a slog or l2arc and put a data partition on it)

 

[jgreco]

You don't have any reasonable room for L2ARC, certainly not hundreds of gigs of it. The ratio of ARC:L2ARC should be about 1:4 or maybe 1:5 unless actual usage patterns show that more is acceptable, but really you shouldn't start adding L2ARC until you have at LEAST 32GB of RAM, strongly preferably 64GB or more. L2ARC robs space from ARC and so may actually hurt performance.

FreeNAS doesn't support using a single device for multiple tasks, and putting L2ARC and SLOG is very bad for performance.

 

[jgreco]

for l2arc plan at least 64gb ram. btw do not slice the ssd, it makes things slow ( so do not mix a slog or l2arc and put a data partition on it)

Or zambanini put it into far fewer words, nice summary.

 

[AndreStarTrek]

keep in mind that these drives are for archiving. write once..read from time to time. see them as tape drives scnr. if a freed sector gets rewritten, the inner and outer tracks (not sectors) will be written completly, since they overlap http://www.hgst.com/sites/default/files/images/science-of-storage/SMR_visual.jpg.

 

[AndreStarTrek]

I read it over again about the L2ARC. I mean ZIL only. It is been about a half year ago that i learn about the working of zfs and freenas. So with no production system yet, some things i need to read again :p