btrfs cache pool not reporting right disk space

[comet424]

so on my 1 unraid server.. i added a 2nd  drive..  my 1TB drive  i use to download to filled up. for all windows downloads game updates etc

 

i added a 2nd drive a 2TB  to add 3TB 

but i guess its mirrored?   as i only get  1.5TB file size...   but the issue says i using   400GB  when really im using 800 GB of data...  and free space is 500GB   i did a reboot and it didnt fix it  

is there a checker to fix the issue?  do i run that scrub  button  to fix it?  krusader shows different... 

 

and the raid1:    picture  that is from clicking the first drive.. the 2nd drive doesnt show it

 

update:

i currently clicked the scrub button but dunno if that will fix it?

Edited February 11, 2022 by comet424

[JorgeB]

Default is raid1, you can convert to single profile to use all the available space.

[comet424]

what does a single profile mean?     i know when i plugged the drive in

 

it said there was too many profiles  and to ignore the error  till btrfs  done balancing

 

so raid 1 is mirror then right?  so shouldnt the diskspace say 844Gb used   not 426gb  used    

as the used gbs would be still wrong  even if i convert to full space

 

the main page reports the wrong disk space used 

 

it says   1.5TB  diskspace in a mirror.. but actually when you add up  Used  + Free space its 998Gb  so its 1TB  yet its missing 500Gb  to equal 1.5TB   

 

main page said  

426gb used    572gb free

Krusader says

844gb used   532gb free

 

the krusader is more accurate then the main page 

 

so i clicked that scrub button to see if it will fix the mainpage saying 426 and fix it to 844gb

Edited February 11, 2022 by comet424

[JorgeB]

7 minutes ago, comet424 said:

the krusader is more accurate then the main page 

It's not, most other utils are not reliable with btrfs for used/free space, GUI will show the correct stats for that pool, except total capacity when in raid1 mode because of the different size devices, used/free are correct though, total capacity would be 1TB, with single profile everything will be correct.

[comet424]

ok i lost

 

when i had a Single Disk   1TB  drive  i filled it up  so it was 800Gb+  Used   (main page and Krusader)

when i added a 2nd Disk   2TB to the drive   Used Space is now in the 400Gb

 

how did   physically  400Gb  go missing?

 

cuz shouldnt it be   

 

800GB used   500 gb free    1.5TB  pool

800GB used   500 gb free    3.0TB pool 

 

 

cuz  the gui is not showing the correct stats of the pool   for used gig

 

main page says   1TB  actuallly

998gb = 1500  gb (1.5tb)   so why is gui page loose 400gb of diskspace at least

 

it should really say

800gb used    500gb free  of 1.5tb free  

 

the math on the GUI page doesnt add up

 

Edited February 11, 2022 by comet424

[JorgeB]

6 minutes ago, comet424 said:

the math on the GUI page doesnt add up

 

24 minutes ago, JorgeB said:

GUI will show the correct stats for that pool, except total capacity when in raid1 mode because of the different size devices

 

[comet424]

so its a glitch/bug then

 

and your said   Total Capacity.. i said  "used space" not "total  capactiy" 

 

as total capacity is different to used space 

 

so what happens if i add a 3rd drive?

so be 1TB 2TB 3TB  does it take the used diskspace from 800gb (single disk ) to 400gb (2 disks)  to 200gb used (3 disks)

is that how the math works

 

so in the end  its best to get same size drives  when doing the mirror  mode... 

 

as i dont mind the mirror option   but i just dont want the gui throwing me errors when math doesnt add up to me its like unraid compressiongs 800 phyiscal data  down to 400 gb physical data

 

to me  it should still say

800 gb used  500gb free of 1.5TB pool 

as to me unraid does super compression  

 

but thanks for the input learn something everyday

if its mixed drive  dont do mirror..  only do  raid 0

if its same sized drive   then u can do mirror propperly 

 

i appreciate it...i just dont want  gui kicking me any errors etc

 

 

[ChatNoir]

You can check what to except with various disk size and number as well as various BTRFS profiles.

https://carfax.org.uk/btrfs-usage/

[comet424]

@ChatNoir  that helped alot  i see   

i see its not good to use  1TB and 2TB drives together...  

Striping the Data Raid 0    says you get 3TB  yet 1TB is unusable  so stripping data is 2TB usuable.. i guess you loose 1TB of data striping the data between 2 odd ball drives

but if its 2 2TB drives no unusable..   

 

if you have 2 1TB  thats ok to Stripe data   if its 2 2TB drives thats ok to Stripe Data.. but if its 1TB and 2TB drive its not good to strip that data  you loose data  shows best to keep it a single Disks..

 

damn odd ball drives i have lol

 

seems if its always an odd ball number you loose data  Stripping data  no matter what   

if you had a 2Tb and a 6TB  stripped to 8TB    only 4TB is usuable and 4TB is unusable too

 

so kinda confusing  but i guess best practice ...   do not mix drives   in the end  for cache    least not odd balls  keep it 2 2 2  or 6 6 6 or 1 1 1 1    sizes  

when you use a 6TB and 2TB Drive stripped  you have 0 disk space you can use in the end

Total space for files:	4000
Total raw disk space:	8000
Unusable:	4000
region 0
Usable	4000
Disks/alloc	2

 

but i guess how it works is 

2TB (2TB drive) + 2TB (6TB drive) = 4 usuable and 4TB left on the 6TB is unusable

 

i guess what the raid0 does is basiclly   what the parity drive does...  only as big as its biggest drive or really smallest drive

 

 

Edited February 11, 2022 by comet424

[comet424]

so i tried the Raid 0 and Single drive and Best Performance i get the 2.57TB free diskspace 

yet  Used disk space is still 427gb   when  used disk space should be 800 and something 

 

might just just move the 800 gig of files  to the array  then redo  the download pool drive remove the 1TB   and then move the 800 gb of files to the 2TB drive it should report 800 gb  or will its report 400gb?

[comet424]

so i have question

 

if the gui main page  orginally said my  1TB cache pool was full as i couldnt write to it anymore..  it was 46gb  and i had min set to 50gb

and when i added the 2nd drive  as you seen above   and it brought down the file size from 1TB less 50gb  down to 400 and something gb

 

does that mean there was lost files   broken files   that unraid said there was files but there wasnt...   

is that what the scrub is for.. to scan the drive and remove the  false file size display.. i remember years ago there was a program for windows

were say it says   100gb  used  but really on a usb  that was only 32gb say   

 

or can u use  TRIM   on a spinner drive?  as i using a spinner  not a SSD

 

and after i moved  the files to the array.. and removed the 2TB drive    and then formated the 1TB  to be a cache pool again..   now when i moved the files back off the array to the download drive.. it no longer reports 1TB  used  in gui main page but 400 used  and like 500 free  for the 1TB  ...  so 500gb was lost  in dead etc?

 

and i do regular  cleaning of the Recyling Bin  so the files werent there..  so what would cause it to balloon  a a move from the pool to the array then basiclly a format i guess then move back fixes it?

 

is there a regular scan  to clean up  the pool?  and does this ever happen on the array?

Edited February 12, 2022 by comet424