Total usable space

[Christopher Ward]

I purchased 10x3tb red drives i have put it in a raidz2 setup, from my calculations i should have 21.8tb from using http://www.servethehome.com/raid-calculator/ but it's only showing as 20.1tb on the mapped network drive?

Would i be correct in thinking im missing 1.7tb and how would i get it back? i'm new to freenas and have only set this up today.

 

[Bidule0hm]

You should get 21.8 TiB minus the overheads. You can also have snapshots taking some space but I can guess you don't have any.

Remember to not use more than 80 % of the pool so you effectively have about 17.5 TiB usable.

 

[Christopher Ward]

I have a pluginjail snapshot apparently but that is only 219KiB what other over heads is there?

 

[Darren Myers]

I have a pluginjail snapshot apparently but that is only 219KiB what other over heads is there?

ZFS overhead itself. With Bidule0hm fancy and handy dandy calculator! You should have around 21Tb and keep 4Tb of that Free, so around 18Tb usable.

 

[Christopher Ward]

ok but it's showing only 20.1tb not 21tb or 21.8tb ?, is the overheads really 1tb + ? i guess this is fine then ?

I upgraded from my 8 drive raid 6 array to freenas and added 2 drives and had hoped to get a little more TB by adding 2 more drives but it doesn't seem that I'll be getting that much more, but if the TB it's showing is fine i guess i'll live with it.

Also is it 2 late if i want to upgrade to 4tb drives in the future, can i swap the 3tbs out one a time to eventually have 10x4tb drives (Extra 10tb ?)

Thanks,
Chris.

 

[Bidule0hm]

As you have 10 drives for a RAID-Z2 I can guess the overhead due to misaligned blocks is pretty high.

Yes, you can totally change the 3 TB drives with 4 TB ones, one at a time, no problem ;)

NB: my calculator is exact on everything but the overheads, there's still some overheads I need to take into account, so take the overhead space with a grain of salt for now.

 

[Christopher Ward]

Ok good I thought I would've had to have created the volume it with at least one 4tb to do that, that makes me happier :D

Cheers guys.

 

[AMiGAmann]

Is the overhead really that big?

I have 8x 6TB drives. Bidule0hm's calculator says the total usable space (RAID-Z2) is 32.74TiB.

I have created a volume and it says the available space is only 30TiB. Where is that missing 2.74TiB?

 

[AMiGAmann]

Nobody?

 

[solarisguy]

Try adding zfs_space parameter to your samba.

See https://forums.freenas.org/index.ph...vfs-modules-is-missing-some-parameters.39107/ for some info (at the bottom).

 

[BigDave]

In regards to the screen shot of the network drive above...
Do keep in mind windoz reports things a bit differently than some other operating systems

 

[joeschmuck]

These questions come up frequently so people having these questions should be doing a search of the forums or just a general google search. If you have just slightly less than you would be expecting after using a RAIDZ calculator, then you are good. If you're missing 10% or more, you may have an issue. Overhead does exist and if someone really wants to learn about it, again the google search would be your friend.

 

[AMiGAmann]

Do keep in mind windoz reports things a bit differently than some other operating system

The sizes I mentioned are both visible in FreeNAS GUI...

These questions come up frequently so people having these questions should be doing a search of the forums or just a general google search. If you have just slightly less than you would be expecting after using a RAIDZ calculator, then you are good. If you're missing 10% or more, you may have an issue.

I have searched a lot in this forum but I still don't understand the sizes mentioned. I am missing nearly 3TB which is 8-9%, so I do think I have an issue.

 

[joeschmuck]

I don't think you have an issue either. A lot of times people will start out fine and then like magic the space starts disappearing. When this happens it's typically snapshots has been turned on and those consume an enormous amount of space. BTW, the 10% was just a value I pulled out my rear, but 3TB does sound like a lot. If you want someone to look at this and make a better informed answer, post the output of "zfs list" and "zpool list".

 

[AMiGAmann]

A lot of times people will start out fine and then like magic the space starts disappearing. When this happens it's typically snapshots has been turned on and those consume an enormous amount of space.

I just created my pool which was empty when I posted the screenshot above.

If you want someone to look at this and make a better informed answer, post the output of "zfs list" and "zpool list".

Here is the output of "zfs list":

Code:

NAME  USED  AVAIL  REFER  MOUNTPOINT
freenas-boot  541M  57.1G  31K  none
freenas-boot/ROOT  534M  57.1G  25K  none
freenas-boot/ROOT/Initial-Install  1K  57.1G  511M  legacy
freenas-boot/ROOT/Pre-FreeNAS-9.3-STABLE-201511040813-178283  1K  57.1G  512M  legacy
freenas-boot/ROOT/default  534M  57.1G  518M  legacy
freenas-boot/grub  6.79M  57.1G  6.79M  legacy
pool  3.21T  26.8T  205K  /mnt/pool
pool/.system  5.23M  26.8T  222K  legacy
pool/.system/configs-db1cb4a536674130995410d4e235f6a8  307K  26.8T  307K  legacy
pool/.system/cores  2.30M  26.8T  2.30M  legacy
pool/.system/rrd-db1cb4a536674130995410d4e235f6a8  205K  26.8T  205K  legacy
pool/.system/samba4  1.62M  26.8T  1.62M  legacy
pool/.system/syslog-db1cb4a536674130995410d4e235f6a8  614K  26.8T  614K  legacy
pool/audio  236G  26.8T  236G  /mnt/pool/audio
pool/daten  388G  26.8T  388G  /mnt/pool/daten
pool/video  2.60T  26.8T  2.60T  /mnt/pool/video

...and here is the output of "zpool list":

Code:

NAME  SIZE  ALLOC  FREE  EXPANDSZ  FRAG  CAP  DEDUP  HEALTH  ALTROOT
freenas-boot  59.5G  541M  59.0G  -  -  0%  1.00x  ONLINE  -
pool  43.5T  4.51T  39.0T  -  5%  10%  1.00x  ONLINE  /mnt

 

[joeschmuck]

I just checked the RAID calculator and it says for a 6TBx8Drives@RAIDZ2, that is 28TB. Your values that you stated above were for a RAIDZ1. Your system is good.

 

[AMiGAmann]

Your values that you stated above were for a RAIDZ1.

Where did you get that 28TB?

If I use Biduleohm's calculator it states "Total data space 32.74TiB", see attached picture.

I know that I should only use 26TB (80%) of that size, but "zfs list" output shows a pool size of 26,8T, which I still don't understand.

 

[joeschmuck]

Nope, I read the wrong thing, that is why I don't use that RAID calculator. So you should have 32.7TB of usable space minus 16GB for SWAP space, so still 32TB. I can see your delima, it does look like you are missing 2TB of storage however I'm sure it's the inefficiencies in the formatting of the partitions, possibly not on a 4k alignment.

but "zfs list" output shows a pool size of 26,8T, which I still don't understand.

That's an easy one, that value is what is estimated as remaining in storage and you need to add 3.21TB that is already used (not part of the overhead) which gives you a total of 30.01TB. Still slightly less than the 32.7TB you were expecting, but ZFS is crappy for estimations.

I know I likely didn't help you but I do not see anything wrong with your pool size. I've just accepted that ZFS isn't a good file system to obtain precise file sizes like becasue it can and is very wasteful.

 

[solarisguy]

Could you please post output of
zfs get quota pool
and
zpool status pool
Thank you!

 

[AMiGAmann]

So you should have 32.7TB of usable space minus 16GB for SWAP space, so still 32TB. I can see your delima, it does look like you are missing 2TB of storage however I'm sure it's the inefficiencies in the formatting of the partitions, possibly not on a 4k alignment.

It's quite astonishing, 2TB is IMHO very lot. I would not have thought that this could be a result of inefficiencies of the file system.

Here is the output of "zfs get quota pool":

Code:

NAME  PROPERTY  VALUE  SOURCE
pool  quota  none  local

...and "zpool status pool":

Code:

  pool: pool
 state: ONLINE
  scan: none requested
config:

  NAME  STATE  READ WRITE CKSUM
  pool  ONLINE  0  0  0
  raidz2-0  ONLINE  0  0  0
  gptid/5cde534a-9211-11e5-94a0-0cc47a693042  ONLINE  0  0  0
  gptid/5d880257-9211-11e5-94a0-0cc47a693042  ONLINE  0  0  0
  gptid/5e2da738-9211-11e5-94a0-0cc47a693042  ONLINE  0  0  0
  gptid/5ed0e983-9211-11e5-94a0-0cc47a693042  ONLINE  0  0  0
  gptid/5f7a55dd-9211-11e5-94a0-0cc47a693042  ONLINE  0  0  0
  gptid/601f935d-9211-11e5-94a0-0cc47a693042  ONLINE  0  0  0
  gptid/60c4caf8-9211-11e5-94a0-0cc47a693042  ONLINE  0  0  0
  gptid/616b14fb-9211-11e5-94a0-0cc47a693042  ONLINE  0  0  0

errors: No known data errors

So everything seems to be fine, except ~2TB are "missing" :-(