Thunderbay Mini

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Thunderbay Mini

Postby merca » Thu Oct 29, 2015 3:03 pm

Hi

I'm planning on ordering an OWC Thunderbay Mini enclosure (4 port 2.5" Thunderbolt 2). And then filling with 4x Samsung Pro 512 drives

I was hoping to go with ZFS for this setup, with emphasis on performance. (I backup continuously so not worried about a drive failure).

What's the best way to go here?
merca
 
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Re: Thunderbay Mini

Postby haer22 » Sun Nov 15, 2015 9:21 am

I you want max performance the pool should be created like
Code: Select all
zpool create -o ashift=12 -O atime=off -O casesensitivity=insensitive -O normalization=formD -O mountpoint=/Volumes/tank tank /dev/disk2 /dev/disk3 /dev/disk4 /dev/disk5

Will give you a RAID-0 a la zfs. The difference will be that you will know when you get corrupted data.

I have the big brother to your box, the one with 3.5" bays. Streaming test data, I "filled" Thunderbolt10. Nice feeling :geek:
haer22
 
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Re: Thunderbay Mini

Postby ilovezfs » Mon Nov 16, 2015 10:21 pm

The saying is, "Friends don't let friends use RAID 0." So be sure you have extremely solid backups, preferably on and off site, if you're going to play with fire.

haer22: Note that you can leave out the "/dev/" from each of those device names for simplicity.
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Re: Thunderbay Mini

Postby merca » Wed Nov 18, 2015 2:59 pm

haer22 wrote:I you want max performance the pool should be created like
Code: Select all
zpool create -o ashift=12 -O atime=off -O casesensitivity=insensitive -O normalization=formD -O mountpoint=/Volumes/tank tank /dev/disk2 /dev/disk3 /dev/disk4 /dev/disk5

Will give you a RAID-0 a la zfs. The difference will be that you will know when you get corrupted data.

I have the big brother to your box, the one with 3.5" bays. Streaming test data, I "filled" Thunderbolt10. Nice feeling :geek:


Great - that sounds like a nice setup. What sort of speeds are you seeing?

If you're up for it, I have a few questions

Turning off atime. Will it still function like a normal OSX hfs+ drive?
ashift=12 - how much diskspace do you lose with this?
does everything work nicely with OSX - or are there gotchas one needs to be aware of?
merca
 
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Re: Thunderbay Mini

Postby haer22 » Thu Nov 19, 2015 7:46 am

merca wrote:Great - that sounds like a nice setup.

As iLovefs noted, raid0 is not "nice", it is dangerous.

My setup of the main pool is:
Code: Select all
[ihecc:~] root# zpool status zeus
  pool: zeus
 state: ONLINE
  scan: scrub repaired 0 in 10h34m with 0 errors on Mon Nov 16 23:53:52 2015
config:

   NAME        STATE     READ WRITE CKSUM
   zeus        ONLINE       0     0     0
     raidz1-0  ONLINE       0     0     0
       disk1   ONLINE       0     0     0
       disk3   ONLINE       0     0     0
       disk4   ONLINE       0     0     0
       disk2   ONLINE       0     0     0
     raidz1-1  ONLINE       0     0     0
       disk15  ONLINE       0     0     0
       disk14  ONLINE       0     0     0
       disk12  ONLINE       0     0     0
       disk7   ONLINE       0     0     0
   logs
     disk5s4   ONLINE       0     0     0
   cache
     disk5s5   ONLINE       0     0     0

errors: No known data errors
[ihecc:~] root# zpool list zeus
NAME   SIZE  ALLOC   FREE  EXPANDSZ   FRAG    CAP  DEDUP  HEALTH  ALTROOT
zeus  21,8T  15,2T  6,60T         -    27%    69%  1.00x  ONLINE  -
disks are all 3TB, log is 8 GB and cache is ca 50 GB. One vddv is in the Thunderbay via Thunerbolt 10, the other vdev is in a eSATA chassi. Loads of small jpegs, quite a few database dumps and a lot of time machine blocks (64MB).
The backup-pool is 6*4TB in a raidz2 setup with compression and dedup.
merca wrote:What sort of speeds are you seeing?

When I scrub, the average rate over the whole scrubbing 470MBps. If I remember correctly it tops just below 600MBps according to "zpool iostat 60".
merca wrote:Turning off atime. Will it still function like a normal OSX hfs+ drive?
No problems what I have seen.
merca wrote:ashift=12 - how much diskspace do you lose with this?
The important issue is not the diskspace, the important issue to align to modern disks which are 4096b/sector. Otherwise the speed will suffer greatly. Also, with the cost of 3TB disks I basically do not care that much about wasting diskspace.
merca wrote:does everything work nicely with OSX - or are there gotchas one needs to be aware of?
It sits on my server so my clients do not see the zfs. So no issue there.
It would be nice to have MacOSX to recognize zfs a bit more, for example as a potential Time Machine "disk".
I used USB3 when I stared playing around with ifs but it wa painful with all the disk renumbering. I have since changed to eSATA and Thunerbolt and now it just works.
haer22
 
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