# ZFS slow after first reboot



## Doublemint (May 16, 2011)

I must admit that I'm fairly new to both FreeBSD and ZFS, but I've searched fairly thoroughly and cannot find a solution to this problem. Basically, I can create a ZFS pool and read/write speeds are fine until the system is restarted. After restarting the system borders on unusable. For the record I'm using 8.2-RELEASE-amd64 with the stock version of zpool (version 15).

Firstly I created a zpool, like so:
`# zpool create tank mirror /dev/ada0 /dev/ada1`

Then I ran a simple write speed test:

```
# dd if=/dev/zero of=/tank/testfile bs=1k count=100000
100000+0 records in
100000+0 records out
102400000 bytes transferred in 1.357105 secs (75454749 bytes/sec)
```

75MB/sec seems pretty reasonable to me. The problem is that after a restart, the same test gives me the following:

```
# dd if=/dev/zero of=/tank/testfile bs=1k count=100000
100000+0 records in
100000+0 records out
102400000 bytes transferred in 26.526750 secs (3860254 bytes/sec)
```

The write speed has now mysteriously dropped to a mere 4MB/sec. This slowness persists indefinitely. The only way I've found to fix it is to destroy and re-create the zpool, which is not workable at all.

I've verified that the same problem happens on different drives and in different configurations (mirror and single drive).

Any ideas guys?
Cheers.


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## Doublemint (May 16, 2011)

Turns out I forgot to add 
	
	



```
zfs_load="YES"
```
 to /etc/rc.conf.

How silly of me. :\


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