[OpenIndiana-discuss] rpool defragmentation

[Gary Gendel]

On 01/16/2015 10:22 AM, Andrew Gabriel wrote:
> On 01/16/15 02:37 PM, Gary Gendel wrote:
>> # zpool list
>> NAME      SIZE  ALLOC   FREE  EXPANDSZ   FRAG    CAP  DEDUP HEALTH 
>> ALTROOT
>> rpool      68G  49.5G  18.5G         -    50%    72%  1.00x ONLINE -
>> users     928G  72.4G   856G         -     1%     7%  1.00x ONLINE -
>>
>> # zfs list
>> NAME                    USED  AVAIL  REFER  MOUNTPOINT
>> rpool                  48.9G  16.9G    82K  /rpool
>> rpool/ROOT             44.9G  16.9G    22K  legacy
>> rpool/ROOT/hipster-17  44.9G  16.9G  34.9G  /
>> rpool/dump             1.97G  16.9G  1.97G  -
>> rpool/export             32K  16.9G    32K  /export
>> rpool/swap             2.01G  16.9G  2.01G  -
>> users                  72.4G   827G  72.3G  /export/home
>>
>> How does one defragment this?
>
> I presume you are referring to rpool, and not users?
>
> What makes you think you need to?
> What do you use the root filesystem for?
>
>> I thought about creating a new BE and then sending the current BE to 
>> it, but there doesn't seem to be enough room.
>
> Since rpool can only be either a single disk or a mirror, the easiest 
> way to defrag it is to attach another mirror side and let it resilver. 
> The new mirror side will be defragged. Make sure the new disk is 
> bootable (has grub etc on it), and then zpool split off the old disk. 
> It would be a good opportunity to move to a bigger rpool disk too.
>
Yes, this is the rpool and is mirrored.  Would resilvering really 
defragment it?

I figured that with this high a fragmentation there would be some 
penalty in memory consumption and possible disk access.  The rpool has 
gotten worse slowly.  This started with somewhere around OpenSolaris 
SNV_124 when the disk requirements were much smaller and has gone though 
100s of updates since then.

I'm hanging on to this SunFire v20z until I can figure out a cheap, less 
power hungry replacement.  It replaced my Sparc SunFire 150 that started 
running OpenSolaris around SNV_62!  In my SOHO, the V20z runs the network:

* Firewall and router WAN to LAN.
*** It would be nice to get a DHCPv6 PD client working so I don't have 
to have a 4-6 tunnel.
* Web server (Web pages, Wiki, Owncloud, etc.)
* File server (user pool and archive pool).
* Archive server.
* Mail server
* DCHP 4 and 6 server.
* Software testing platform.

Most of the time this machine is lightly loaded.  Only when software 
testing goes on does it ever sweat.  It's kind of a kludge setup as I 
have the disks off of sata cables directly from the controller to the 
disks in an external cabinet because of the lack of sata multiplexing.

Gary