# ZFS: Adding disk and changing to RAIDZ2



## bsus (Jul 5, 2011)

Hi,

As I have configured my FreeBSD server (and already created a ZFS filesystem) one drive failed and I "reinstalled" the complete ZFS. To four disks and RAIDZ now. I have got a new drive which I want to add to the storage. I also want to change the RAIDZ to a RAIDZ2. Is this possible or do I have to make a ZFS from new?

4x 2TB WD Caviar Green [ZFS RAIDZ] => 5x 2TB WD Caviar Green [ZFS RAIDZ2]

Regards


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## SirDice (Jul 5, 2011)

bsus said:
			
		

> I also want to change the RAIDz to a RAIDz2. Is this possabil or do I have to make a ZFS from new?


You will have to back up your data and recreate the zpool from scratch.


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## rusty (Jul 5, 2011)

You'll have to re-make the pool. 

Couple of questions it may be worth looking into before building the RAIDZ2. What is the state of play regarding WD Green's 4K reporting to the OS? Does the head parking time need to be altered?


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## bsus (Jul 5, 2011)

> What is the state of play regarding WD Green's 4K reporting to the OS


I am not sure but I think this is negligible.



> Does the head parking time need to be altered?


The parking time (I think) is from default still to low. So the head will move quite a lot. But this issue is on all OS's, that's why I want to have a RAID6. Also there's a first help extra drive which I can't connect after another fails and which then gets resilvered. The broken is going way back to WD - not the finest solution but it will work.


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## rusty (Jul 5, 2011)

Both 4K and head parking are known problems with the Caviar Green range, there are workarounds for them which would be very beneficial before you put loads of data on the pool.

Your low write speed mentioned in another thread is very likely related to WD's crappy 4K implementation, gnop and/or ashift=12 is what you'll need to search for. Loads of threads on these forums covering this.

Re: head parking
http://forums.freebsd.org/showthread.php?t=13222&highlight=head+parking


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## bsus (Jul 5, 2011)

Ok, you have persuaded me. I have read through the thread and except the little beef at the bottom there wasn't so much detailed information to dos and widle 3.

Is there a good detailed tutorial about this problem which you could recommend me?


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## bsus (Jul 5, 2011)

I now just asked google a little bit and found this tutorial
In the red box I can read: 





> Affected, according to Western Digital are the only models WD1000FYPS-01ZKB0, WD7500AYPS 01ZKB0-and-WD7501AYPS 01ZKB0. For other models discussed here the firmware update is not recommended!



I now tried the smartctl command on another 24/7 share server with two WD Caviar green 2TB in RAID1 on Gentoo.

```
smartctl -A /dev/sdb | egrep "ID|Load|Power"
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  9 Power_On_Hours          0x0032   098   098   000    Old_age   Always       -       1987
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       46
192 Power-Off_Retract_Count 0x0032   200   200   000    Old_age   Always       -       36
193 Load_Cycle_Count        0x0032   194   194   000    Old_age   Always       -       19592
```

The server is running since April.

Unforunately the system drive is one of the affected one, see:

```
ctl -A /dev/sda | egrep "ID|Load|Power"
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  9 Power_On_Hours          0x0032   098   098   000    Old_age   Always       -       1985
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       47
192 Power-Off_Retract_Count 0x0032   200   200   000    Old_age   Always       -       39
193 Load_Cycle_Count        0x0032   178   178   000    Old_age   Always       -       68526
```

This has 3 times more park progresses.

So, now checked a WD Caviar Blue 320GB running 24/7 since 2 years:

```
smartctl -A -s on /dev/sda | egrep "ID|Load|Power"
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  9 Power_On_Hours          0x0032   089   089   000    Old_age   Always       -       8209
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       910
192 Power-Off_Retract_Count 0x0032   200   200   000    Old_age   Always       -       291
193 Load_Cycle_Count        0x0032   200   200   000    Old_age   Always       -       1047
```


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