SOLVED ZFS Dataset question-Creating an Area on the Boot Drive for Custom Scripts

[NASbox]

Here's the TLDR;

So IIUC, it appears that for someone starting from scratch the steps would be:

zfs create freenas-boot/CUSTOM
zfs set mountpoint=/CUSTOM freenas-boot/CUSTOM
zfs set canmount=on freenas-boot/CUSTOM
zfs mount freenas-boot/CUSTOM

the dataset /CUSTOM is now available and ready for use.

Obviously it makes good sense to replicate to the storage pool or another system for backup, (especially before running an update) but this strategy appears to be a very viable way to keep custom scripts available even if the storage pool is offline.

================================================================

I know this isn't considered a best practice/supported action, but for maintenance I want a dataset "CUSTOM" on the boot pool so that my maintenance scripts are available if for some reason I have my main pool off line. This has been working well, but now I need to learn how to manage an upgrade (I've got lots of backup copies if I need to destroy the pool and recreate it.)

I just went through the process of upgrading from 11.1-Release to 11.1U4, and I need a little bit of guidance with migrating my CUSTOM Datatset.
Before the upgrade, things looked like this:

Code:

#>zfs list -t all -r freenas-boot/ROOT/11.1-RELEASE/CUSTOM
NAME															 USED  AVAIL  REFER  MOUNTPOINT
freenas-boot/ROOT/11.1-RELEASE/CUSTOM						   82.3M   103G  81.7M  /CUSTOM
freenas-boot/ROOT/11.1-RELEASE/CUSTOM@CUSTOM_2018-04-15_232104   104K	  -  81.6M  -
freenas-boot/ROOT/11.1-RELEASE/CUSTOM@CUSTOM_2018-04-16_054026	72K	  -  81.6M  -
freenas-boot/ROOT/11.1-RELEASE/CUSTOM@CUSTOM_2018-04-18_064920   112K	  -  81.7M  -
freenas-boot/ROOT/11.1-RELEASE/CUSTOM@CUSTOM_2018-04-19_054729   112K	  -  81.7M  -
freenas-boot/ROOT/11.1-RELEASE/CUSTOM@CUSTOM_2018-04-21_233201   148K	  -  81.7M  -
freenas-boot/ROOT/11.1-RELEASE/CUSTOM@CUSTOM_2018-04-23_204519	  0	  -  81.7M  -
freenas-boot/ROOT/11.1-RELEASE/CUSTOM@CUSTOM_2018-05-03_004248	  0	  -  81.7M  -

after the upgrade they look like this:

Code:

freenas-boot																   5.24G   102G   176K  none
freenas-boot/.system															110M   102G  4.34M  legacy
freenas-boot/.system/configs-66c5ca0d9b594eb08a0e7191ec86e4a6				  19.6M   102G  19.6M  legacy
freenas-boot/.system/configs-9d613bc4d69d4caa9ab03b2439285b53				   136K   102G   136K  legacy
freenas-boot/.system/cores													 16.1M   102G  16.1M  legacy
freenas-boot/.system/rrd-66c5ca0d9b594eb08a0e7191ec86e4a6					  28.2M   102G  28.2M  legacy
freenas-boot/.system/rrd-9d613bc4d69d4caa9ab03b2439285b53					  3.85M   102G  3.85M  legacy
freenas-boot/.system/samba4													 496K   102G   496K  legacy
freenas-boot/.system/syslog-66c5ca0d9b594eb08a0e7191ec86e4a6				   36.8M   102G  36.8M  legacy
freenas-boot/.system/syslog-9d613bc4d69d4caa9ab03b2439285b53					296K   102G   296K  legacy
freenas-boot/ROOT															  5.11G   102G   136K  none
freenas-boot/ROOT/11.0-U3													   232K   102G   970M  /
freenas-boot/ROOT/11.0-U4													   248K   102G   973M  /
freenas-boot/ROOT/11.1-RELEASE												  432K   102G  1.08G  /
freenas-boot/ROOT/11.1-RELEASE/CUSTOM											 8K   102G  81.7M  /CUSTOM
freenas-boot/ROOT/11.1-U4													  5.11G   102G  1.09G  /
freenas-boot/ROOT/11.1-U4@2017-09-20-01:21:53								  4.05M	  -   980M  -
freenas-boot/ROOT/11.1-U4@2017-09-19-23:36:41								  4.06M	  -   980M  -
freenas-boot/ROOT/11.1-U4@2017-09-29-02:04:28								   969M	  -   970M  -
freenas-boot/ROOT/11.1-U4@2017-12-15-20:16:16								   971M	  -   973M  -
freenas-boot/ROOT/11.1-U4@2018-05-03-01:15:15								  1.08G	  -  1.08G  -
freenas-boot/ROOT/11.1-U4/CUSTOM											   82.4M   102G  81.7M  /CUSTOM
freenas-boot/ROOT/11.1-U4/CUSTOM@CUSTOM_2018-04-15_232104					   104K	  -  81.6M  -
freenas-boot/ROOT/11.1-U4/CUSTOM@CUSTOM_2018-04-16_054026						72K	  -  81.6M  -
freenas-boot/ROOT/11.1-U4/CUSTOM@CUSTOM_2018-04-18_064920					   112K	  -  81.7M  -
freenas-boot/ROOT/11.1-U4/CUSTOM@CUSTOM_2018-04-19_054729					   112K	  -  81.7M  -
freenas-boot/ROOT/11.1-U4/CUSTOM@CUSTOM_2018-04-21_233201					   148K	  -  81.7M  -
freenas-boot/ROOT/11.1-U4/CUSTOM@CUSTOM_2018-04-23_204519						  0	  -  81.7M  -
freenas-boot/ROOT/11.1-U4/CUSTOM@CUSTOM_2018-05-03_004248						  0	  -  81.7M  -
freenas-boot/ROOT/11.1-U4/CUSTOM@2018-05-03-01:15:15							   0	  -  81.7M  -
freenas-boot/ROOT/Initial-Install												 8K   102G   980M  legacy
freenas-boot/ROOT/default													   232K   102G   980M  legacy
freenas-boot/grub															  7.80M   102G  7.80M  legacy

When I initially tried to access /CUSTOM/ all I got was an empty directory. I was able to access my data (and the mount was Read/Write) by executing the command: zfs mount -v freenas-boot/ROOT/11.1-RELEASE/CUSTOM, but my sense is that this isn't what I should be doing as the new boot dataset is freenas-boot/ROOT/11.1-U4.

I would like to continue forward with freenas-boot/ROOT/11.1-U4/CUSTOM and eventually destroy freenas-boot/ROOT/11.1-RELEASE sometime in the future when I am certain that I won't need to roll it back.

I Tried the following:

Code:

#>umount /CUSTOM/
#>ls -la /CUSTOM/
total 17
drwxr-xr-x   2 root  wheel   2 Jan  5 01:49 .
drwxr-xr-x  24 root  wheel  31 May  3 01:33 ..
#>zfs mount -v freenas-boot/ROOT/11.1-U4/CUSTOM
cannot mount 'freenas-boot/ROOT/11.1-U4/CUSTOM': 'canmount' property is set to 'off'

but I was not able to mount 11.1-U4 - Why?

I'm also confused as to why both freenas-boot/ROOT/11.1-U4/CUSTOM and freenas-boot/ROOT/11.1-RELEASE/CUSTOM show that they are mounted as /CUSTOM - unless I am missing something, only one dataset can occupy a mount point.

Should be exporting the 11.1-Release pool?

I have a symlink to the mountpoint from root - could this be causing the problem?

Code:

#>ls -la /root/CUSTOM
lrwxr-xr-x  1 root  wheel  7 Jan 15 00:10 /root/CUSTOM -> /CUSTOM

I can easily delete/recreate later if necesary.

For now zfs mount -v freenas-boot/ROOT/11.1-RELEASE/CUSTOM seems to work, but I'm sure it's not what I should be doing.

Any hints/suggestions would be much appreciated. This doesn't appear it should be difficult to solve, but there are obviously a couple of fine points that I'm missing.

 

[Ericloewe]

Your problem is that you're placing user data in the middle of OS stuff. That's the wrong approach.

Make a new dataset one level from the top, freenas-boot/custom and you'll be good to go, until the boot pool dies. You can mount it automatically with a script, too.

 

[NASbox]

Your problem is that you're placing user data in the middle of OS stuff. That's the wrong approach.

Make a new dataset one level from the top, freenas-boot/custom and you'll be good to go, until the boot pool dies. You can mount it automatically with a script, too.

Thanks... that helped. I stumbled my way through-likely not an optimal solution, but I'll do my best to document what I did hoping it will be helpful to others.

I had a bit of difficulty creating the pool and getting the data into it, so I took a bit of an indirect route-did a bit of renaming to make sure I didn't have a name collision

Code:

zfs create freenas-boot/CUST
zfs send -vR freenas-boot/ROOT/11.1-U4/CUSTOM@2018-05-03-01:15:15 | zfs recv -ve freenas-boot/CUST
zfs rename freenas-boot/CUST freenas-boot/CUSTOM
zfs rename freenas-boot/ROOT/11.1-U4/CUSTOM freenas-boot/ROOT/11.1-U4/OLD-CUSTOM
zfs rename freenas-boot/ROOT/11.1-RELEASE/CUSTOM freenas-boot/ROOT/11.1-RELEASE/OLD-CUSTOM
zfs send -vR freenas-boot/CUST/CUSTOM@2018-05-03-01:15:15 | zfs recv -ve freenas-boot

This was a bit tricky - I could not mount the new dataset until I ran the following commands:

Code:

zfs set mountpoint=/CUSTOM freenas-boot/CUSTOM
zfs set canmount=on freenas-boot/CUSTOM
zfs mount freenas-boot/CUSTOM

Did I do the right thing? Will this pool automatically remount when I reboot like the old one did, or do I have to do something to make that happen?

Here's the state of the boot drive now:

Code:

NAME															USED  AVAIL  REFER  MOUNTPOINT
freenas-boot												   5.32G   102G   176K  none
freenas-boot/.system											104M   102G  4.34M  legacy
freenas-boot/.system/configs-66c5ca0d9b594eb08a0e7191ec86e4a6  19.7M   102G  19.7M  legacy
freenas-boot/.system/configs-9d613bc4d69d4caa9ab03b2439285b53   136K   102G   136K  legacy
freenas-boot/.system/cores									 16.1M   102G  16.1M  legacy
freenas-boot/.system/rrd-66c5ca0d9b594eb08a0e7191ec86e4a6	  27.7M   102G  27.7M  legacy
freenas-boot/.system/rrd-9d613bc4d69d4caa9ab03b2439285b53	  3.85M   102G  3.85M  legacy
freenas-boot/.system/samba4									 496K   102G   496K  legacy
freenas-boot/.system/syslog-66c5ca0d9b594eb08a0e7191ec86e4a6   31.0M   102G  31.0M  legacy
freenas-boot/.system/syslog-9d613bc4d69d4caa9ab03b2439285b53	296K   102G   296K  legacy
freenas-boot/CUSTOM											82.3M   102G  81.7M  /CUSTOM
freenas-boot/CUSTOM@CUSTOM_2018-04-15_232104					104K	  -  81.6M  -
freenas-boot/CUSTOM@CUSTOM_2018-04-16_054026					 72K	  -  81.6M  -
freenas-boot/CUSTOM@CUSTOM_2018-04-18_064920					112K	  -  81.6M  -
freenas-boot/CUSTOM@CUSTOM_2018-04-19_054729					112K	  -  81.6M  -
freenas-boot/CUSTOM@CUSTOM_2018-04-21_233201					148K	  -  81.7M  -
freenas-boot/CUSTOM@CUSTOM_2018-04-23_204519					   0	  -  81.7M  -
freenas-boot/CUSTOM@CUSTOM_2018-05-03_004248					   0	  -  81.7M  -
freenas-boot/CUSTOM@2018-05-03-01:15:15							0	  -  81.7M  -
freenas-boot/ROOT											  5.11G   102G   136K  none
freenas-boot/ROOT/11.0-U3									   232K   102G   970M  /
freenas-boot/ROOT/11.0-U4									   248K   102G   973M  /
freenas-boot/ROOT/11.1-RELEASE								  552K   102G  1.08G  /
freenas-boot/ROOT/11.1-RELEASE/OLD-CUSTOM					   128K   102G  81.7M  /OLD-CUSTOM
freenas-boot/ROOT/11.1-U4									  5.11G   102G  1.09G  /
freenas-boot/ROOT/11.1-U4@2017-09-20-01:21:53				  4.05M	  -   980M  -
freenas-boot/ROOT/11.1-U4@2017-09-19-23:36:41				  4.06M	  -   980M  -
freenas-boot/ROOT/11.1-U4@2017-09-29-02:04:28				   969M	  -   970M  -
freenas-boot/ROOT/11.1-U4@2017-12-15-20:16:16				   971M	  -   973M  -
freenas-boot/ROOT/11.1-U4@2018-05-03-01:15:15				  1.08G	  -  1.08G  -
freenas-boot/ROOT/11.1-U4/OLD-CUSTOM						   82.4M   102G  81.7M  /OLD-CUSTOM
freenas-boot/ROOT/11.1-U4/OLD-CUSTOM@CUSTOM_2018-04-15_232104   104K	  -  81.6M  -
freenas-boot/ROOT/11.1-U4/OLD-CUSTOM@CUSTOM_2018-04-16_054026	72K	  -  81.6M  -
freenas-boot/ROOT/11.1-U4/OLD-CUSTOM@CUSTOM_2018-04-18_064920   112K	  -  81.7M  -
freenas-boot/ROOT/11.1-U4/OLD-CUSTOM@CUSTOM_2018-04-19_054729   112K	  -  81.7M  -
freenas-boot/ROOT/11.1-U4/OLD-CUSTOM@CUSTOM_2018-04-21_233201   148K	  -  81.7M  -
freenas-boot/ROOT/11.1-U4/OLD-CUSTOM@CUSTOM_2018-04-23_204519	  0	  -  81.7M  -
freenas-boot/ROOT/11.1-U4/OLD-CUSTOM@CUSTOM_2018-05-03_004248	  0	  -  81.7M  -
freenas-boot/ROOT/11.1-U4/OLD-CUSTOM@2018-05-03-01:15:15		   0	  -  81.7M  -
freenas-boot/ROOT/Initial-Install								 8K   102G   980M  legacy
freenas-boot/ROOT/default									   232K   102G   980M  legacy
freenas-boot/grub											  7.80M   102G  7.80M  legacy

I would assume that it should be safe to

Code:

zfs destroy -r freenas-boot/ROOT/11.1-RELEASE/OLD-CUSTOM
zfs destroy -r freenas-boot/ROOT/11.1-U4/OLD-CUSTOM

Can someone confirm that that won't screw up the FreeNAS code by destroying freenas-boot/ROOT/11.1-RELEASE/OLD-CUSTOM & freenas-boot/ROOT/11.1-U4/OLD-CUSTOM? IIUC these are my datasets and getting rid of them shouldn't create any problems with the core system.

All I need now is to figure out the auto-mount and I should be good. To be on the safe side, I'll regularly zfs send|recv to the main pool as a backup.

 

[Ericloewe]

I had a bit of difficulty creating the pool and getting the data into it, so I took a bit of an indirect route-did a bit of renaming to make sure I didn't have a name collision

The dataset, you mean?

I don't really understand why you did that circuitous route. zfs create current, zfs send oldcurrent | recv newcurrent

Did I do the right thing? Will this pool automatically remount when I reboot like the old one did, or do I have to do something to make that happen?

Probably. It not, automate the last step with a startup script.

<quote not available due to technical issues>
Re: Deletion. Yes, delete away. I mean, worst case would be that you have to reinstall FreeNAS. You could do that twelve times in the time it takes a Windows 7 machine to run Windows Update. And it's not going to come to that.

 

[NASbox]

The dataset, you mean?

I don't really understand why you did that circuitous route. zfs create current, zfs send oldcurrent | recv newcurrent

Probably. It not, automate the last step with a startup script.

<quote not available due to technical issues>
Re: Deletion. Yes, delete away. I mean, worst case would be that you have to reinstall FreeNAS. You could do that twelve times in the time it takes a Windows 7 machine to run Windows Update. And it's not going to come to that.

I was trying to get everything rolled up under /CUSTOM, and I when I simulated using -evn I was getting a huge long path, and I was afraid of accidentally overwriting something. I ended up doing it incorrectly several times, but I just kept messing around till I got what I wanted and then renamed accordingly.

I find zfs send/recv very complicated and for me the documentation is lacking. It needs a lot more examples to show how things work.

I was going to ask about a "startup script', but it seems as if zfs remembers what is mounted when the system is rebooted. If the canmount parameter is ON and the mountpoint parameter is set to a path, the dataset auto mounts right where it should.

For the record here's the final state of the boot pool after cleanup:

Code:

NAME															USED  AVAIL  REFER  MOUNTPOINT
freenas-boot												   5.24G   102G   176K  none
freenas-boot/.system											106M   102G  4.34M  legacy
freenas-boot/.system/configs-66c5ca0d9b594eb08a0e7191ec86e4a6  19.7M   102G  19.7M  legacy
freenas-boot/.system/configs-9d613bc4d69d4caa9ab03b2439285b53   136K   102G   136K  legacy
freenas-boot/.system/cores									 16.1M   102G  16.1M  legacy
freenas-boot/.system/rrd-66c5ca0d9b594eb08a0e7191ec86e4a6	  27.7M   102G  27.7M  legacy
freenas-boot/.system/rrd-9d613bc4d69d4caa9ab03b2439285b53	  3.85M   102G  3.85M  legacy
freenas-boot/.system/samba4									 496K   102G   496K  legacy
freenas-boot/.system/syslog-66c5ca0d9b594eb08a0e7191ec86e4a6   33.1M   102G  33.1M  legacy
freenas-boot/.system/syslog-9d613bc4d69d4caa9ab03b2439285b53	296K   102G   296K  legacy
freenas-boot/CUSTOM											82.1M   102G  81.7M  /CUSTOM
freenas-boot/CUSTOM@CUSTOM_2018-04-19_054729					168K	  -  81.6M  -
freenas-boot/CUSTOM@CUSTOM_2018-04-21_233201					148K	  -  81.7M  -
freenas-boot/CUSTOM@CUSTOM_2018-04-23_204519					   0	  -  81.7M  -
freenas-boot/CUSTOM@CUSTOM_2018-05-03_004248					   0	  -  81.7M  -
freenas-boot/CUSTOM@CUSTOM_2018-05-03_011515					   0	  -  81.7M  -
freenas-boot/CUSTOM@CUSTOM_2018-05-04_002614					  8K	  -  81.7M  -
freenas-boot/ROOT											  5.03G   102G   136K  none
freenas-boot/ROOT/11.0-U3									   232K   102G   970M  /
freenas-boot/ROOT/11.0-U4									   248K   102G   973M  /
freenas-boot/ROOT/11.1-RELEASE								  424K   102G  1.08G  /
freenas-boot/ROOT/11.1-U4									  5.03G   102G  1.09G  /
freenas-boot/ROOT/11.1-U4@2017-09-20-01:21:53				  4.05M	  -   980M  -
freenas-boot/ROOT/11.1-U4@2017-09-19-23:36:41				  4.06M	  -   980M  -
freenas-boot/ROOT/11.1-U4@2017-09-29-02:04:28				   969M	  -   970M  -
freenas-boot/ROOT/11.1-U4@2017-12-15-20:16:16				   971M	  -   973M  -
freenas-boot/ROOT/11.1-U4@2018-05-03-01:15:15				  1.08G	  -  1.08G  -
freenas-boot/ROOT/Initial-Install								 8K   102G   980M  legacy
freenas-boot/ROOT/default									   232K   102G   980M  legacy
freenas-boot/grub											  7.80M   102G  7.80M  legacy

I assume these snapshots

Code:

freenas-boot/ROOT/11.1-U4@2017-09-20-01:21:53				  4.05M	  -   980M  -
freenas-boot/ROOT/11.1-U4@2017-09-19-23:36:41				  4.06M	  -   980M  -
freenas-boot/ROOT/11.1-U4@2017-09-29-02:04:28				   969M	  -   970M  -
freenas-boot/ROOT/11.1-U4@2017-12-15-20:16:16				   971M	  -   973M  -
freenas-boot/ROOT/11.1-U4@2018-05-03-01:15:15				  1.08G	  -  1.08G  -

were created by the update process and where not as a result of my activity with snapshots I made when custom was under freenas-boot/ROOT/11.1-RELEASE