zfs discuss - Mar 2009 - After createing zpool of combined 750gb only 229 shows

Summary:
I''m doing something wrong here but not sure what.  Put a 250gb and
500gb disk into zpool but only 229gb is available

I have a 250 gb disk and a 500gb disk installed and configured as
raidz1. both have efi labels when viewed with format/fdisk.

fdisk c3d1:
        Total disk size is 30401 cylinders
        Cylinder size is 16065 (512 byte) blocks

                                          Cylinders
 Partition   Status    Type          Start   End   Length    %
 =========   ======    ============  =====   ===   ======   ==     1            
EFI               0  30401    30402    100

fdisk c4d0:
        Total disk size is 60800 cylinders
        Cylinder size is 16065 (512 byte) blocks

                                          Cylinders
 Partition   Status    Type          Start   End   Length    %
 =========   ======    ============  =====   ===   ======   ==     1            
EFI               0  60800    60801    100


After creating the zpool with:
zpool create zbk raidz1 c3d1(250gb) c4d0(500gb) (with no errors)

  zpool status zbk
   pool: zbk
  state: ONLINE
  scrub: none requested
 config:

        NAME        STATE     READ WRITE CKSUM
        zbk         ONLINE       0     0     0
          raidz1    ONLINE       0     0     0
            c3d1    ONLINE       0     0     0
            c4d0    ONLINE       0     0     0

 errors: No known data errors


But then df -h shows only 229gb available

 df -h /zbk
 Filesystem            Size  Used Avail Use% Mounted on
 zbk                   229G   22K  229G   1% /zbk

On 15 March, 2009 - Harry Putnam sent me these 1,7K bytes:
> 
> Summary:
> I''m doing something wrong here but not sure what.  Put a 250gb and
> 500gb disk into zpool but only 229gb is available
> 
> I have a 250 gb disk and a 500gb disk installed and configured as
> raidz1. both have efi labels when viewed with format/fdisk.
> 
> fdisk c3d1:
>         Total disk size is 30401 cylinders
>         Cylinder size is 16065 (512 byte) blocks
> 
>                                           Cylinders
>  Partition   Status    Type          Start   End   Length    %
>  =========   ======    ============  =====   ===   ======   ==>      1  
EFI               0  30401    30402    100
> 
> fdisk c4d0:
>         Total disk size is 60800 cylinders
>         Cylinder size is 16065 (512 byte) blocks
> 
>                                           Cylinders
>  Partition   Status    Type          Start   End   Length    %
>  =========   ======    ============  =====   ===   ======   ==>      1  
EFI               0  60800    60801    100
> 
> 
> After creating the zpool with:
> zpool create zbk raidz1 c3d1(250gb) c4d0(500gb) (with no errors)
> 
>   zpool status zbk
>    pool: zbk
>   state: ONLINE
>   scrub: none requested
>  config:
> 
>         NAME        STATE     READ WRITE CKSUM
>         zbk         ONLINE       0     0     0
>           raidz1    ONLINE       0     0     0
>             c3d1    ONLINE       0     0     0
>             c4d0    ONLINE       0     0     0
> 
>  errors: No known data errors
> 
> 
> But then df -h shows only 229gb available
> 
>  df -h /zbk
>  Filesystem            Size  Used Avail Use% Mounted on
>  zbk                   229G   22K  229G   1% /zbk
You are using raidz1 (which is less useful when you just have 2 disks,
use a mirror instead for same safety but higher performance) which
can''t
use more space than the smallest disk.. so half of the larger disk is
unused in this case. 250 vs 229GB is 1000 vs 1024 when counting MB/kB
etc.

For redundant storage, use disks of the same size.. If you just want to
add up both disks together (and lose all data if one disk goes belly
up), create it with: zpool create zkb c3d1 c4d0

I seem to recall that ZFS should complain and point out that they are
of (major) different size.. But apparently not..

/Tomas
-- 
Tomas ?gren, stric at acc.umu.se, http://www.acc.umu.se/~stric/
|- Student at Computing Science, University of Ume?
`- Sysadmin at {cs,acc}.umu.se

Tomas ?gren <stric at acc.umu.se> writes:
> I seem to recall that ZFS should complain and point out that they are
> of (major) different size.. But apparently not..
Thanks for the tips.

It actually did complain about size difference at one point.  I used
the -f option.  But later destroyed the zpool I''d created that way.

I thought the problem had something to do with fdisk partitions so
fdisked and deleted all partitions.  (There was 1 on each drive).

After that when I created the raidz1 with those two there was no
complaint so I thought I was walking in tall cotton.  Only later when
I ran df -h and saw that zfs had reduced the zpool to lowest disk
size did I realize I didn''t really understand what I was doing.

Your tips summarize what I''d already found on line before seeing your
post.  Very useful to hear from experienced user on this.