Sorry if this is a very basic set of questions.  Unfortunately, the wiki seems a bit outdated, and has conflicting information, and the forums are incredibly difficult to search.

 

I'm running out of storage space on my server, and also running out of physical space to install drives.  So I bought a new 10TB WD datacenter HDD to install as parity.  I then want to move the current 6TB parity disk to replace one of my 3TB data disks.

 

I know next to nothing about Linux and every time I need to change something on my unRAID server, I have to read the wiki and figure out how to use Putty and copy instructions letter for letter from the wiki.

 

With that context, it seems that upgrading the Parity disk is pretty simple.  Ensure that nothing is being changed on the array, shut down server, physically swap the disks, then restart the server and it will automatically rebuild?

 

Is there no need to pre-clear the new drive?

 

I read somewhere that there's a safe mode that can be booted into to ensure that nothing tries to write to the array, but it's not obvious how to boot into this mode.

 

Can I read files from the array while the parity drive is being rebuilt?  Even if it's in safe mode?

 

Thanks for your help!

10 minutes ago, datruedave said:

Ensure that nothing is being changed on the array, shut down server, physically swap the disks, then restart the server and it will automatically rebuild?

 

Almost, you'll need to assign the new parity and start the array to begin the parity sync.

 

10 minutes ago, datruedave said:

Is there no need to pre-clear the new drive?

 

No, although some like to do it for testing purposes.

 

11 minutes ago, datruedave said:

I read somewhere that there's a safe mode that can be booted into to ensure that nothing tries to write to the array

 

Safe mode boots without plugins, not needed in this case

 

11 minutes ago, datruedave said:

Can I read files from the array while the parity drive is being rebuilt?  Even if it's in safe mode?

 

Yes but avoid big transfers as it will slow down the rebuild.

Also if you don't change nothing in the array you can use the old parity if anything goes wrong, you lose that option if there are any writes to the array.

32 minutes ago, johnnie.black said:

Safe mode boots without plugins, not needed in this case

 

 

Yes but avoid big transfers as it will slow down the rebuild.

Also if you don't change nothing in the array you can use the old parity if anything goes wrong, you lose that option if there are any writes to the array.

The main use for my unRaid is as a media server using Plex (via Phaze plugins) and all of the Plex data is on the array. 

 

Are you saying that I can even write to my server while the parity is rebuilding? 

 

Is there a way to simply shut down the mover so that writes are postponed until successful parity rebuild?  (and therefore have the option of using the old parity disk if anything goes wrong)

 

Thanks for the quick response!

 

Edited May 20, 20179 yr by datruedave

1 minute ago, datruedave said:

Are you saying that I can even write to my server while the parity is rebuilding?

 

Yes

 

1 minute ago, datruedave said:

Is there a way to simply shut down the mover so that writes are postponed until successful parity rebuild?  (and therefore have the option of using the old parity disk if anything goes wrong)

 

Not shutdown but you can reschedule it for tomorrow or later if needed.

This might be helpful.

 

Not writing to the array enables rebuilding a drive should one fail while building the new parity if you follow the directions below.

 

 

11 hours ago, bjp999 said:

This might be helpful.

 

Not writing to the array enables rebuilding a drive should one fail while building the new parity if you follow the directions below.

 

 

Excellent.  Thanks!

 

Sorry, but I have one last question:

 

How do I absolutely ensure that I don't write to the array? (This is a family file/media server and I don't completely trust them not to save stuff.)  Does postponing the mover suffice?  Is that the only thing that writes to the array, even if I'm using plugins?

 

1 hour ago, datruedave said:

How do I absolutely ensure that I don't write to the array?

 

When doing the parity upgrade start the array in maintenance mode.

On 5/21/2017 at 1:33 AM, johnnie.black said:

 

When doing the parity upgrade start the array in maintenance mode.

My apologies for the basic questions, but if it's not found in the wiki, or the forums FAQ, or someone explains it to me, I probably don't know how to do it.

 

When I start my server, the array usually starts automatically.  I'm taking note of these two steps:

Quote

5. Note the placement of all the disks and what slots they are assigned to.

 

6. Do a new configuration, and assign the new parity, all data disks to their respective slots. And assign the current parity to the next data slot (if you intend to use it as a data drive)

 

And those steps, combined with your comment, have given me two questions to ask:

 

Is all of the placement and slot information located on the "Main" screen of unRAID?  So if I just save a screenshot of that before I shutdown my server to upgrade this disk, that's all I need to assign everything later?

 

The second question is about starting the array in maintenance mode.  When I restart my server, is unRAID going to see that the parity disk has changed, flag that, and not start the array automatically?  None of the instructions indicate that, and I've never done this, so I want to make sure I get this straight before I mess around with my perfectly functioning server.  It's got almost 30TB of files on it, some irreplaceable, and those that are replaceable are still cherished because my internet connection is a 1MB DSL line.  Downloading stuff takes FOREVER.

Edited May 27, 20179 yr by datruedave
typo

14 minutes ago, datruedave said:

I want to make sure I get this straight before I mess around with my perfectly functioning server.  It's got almost 30TB of files on it, some irreplaceable, and those that are replaceable are still cherished because my internet connection is a 1MB DSL line.

Don't mess with a perfectly functioning server until you have a full backup of anything you aren't willing to lose.

 

Period.

Just now, jonathanm said:

Don't mess with a perfectly functioning server until you have a full backup of anything you aren't willing to lose.

 

Period.

The photos are irreplaceable, but they're backed up.  The rest of the media is replaceable, but a lot of time and effort went into getting it on the server.  My understanding of unRAID is that the risks are pretty minimal.  I'm ready for a small risk, but, again, I want to do everything correctly in an attempt to keep the risks truly minimal.  I've already run all the extended SMART reports on all of my disks.  They all look good.  If the disks are good, and I do everything correctly, then I think the only risks really are from freak accidents, which are a risk right now.  I'm ready to do this as soon as I'm sure of the correct procedure.

 

And, my understanding is that if I save the old parity disk until the new parity has been rebuilt, then even if something does go wrong, I should be able to revert to the old parity disk and replace some other disk that goes bad, right?  And once that disk has been rebuilt, I can attempt this parity replacement again.

12 minutes ago, datruedave said:

And, my understanding is that if I save the old parity disk until the new parity has been rebuilt, then even if something does go wrong, I should be able to revert to the old parity disk and replace some other disk that goes bad, right?  And once that disk has been rebuilt, I can attempt this parity replacement again.

Yes, PROVIDING that there is NO usage of the server while you're building the new parity disk.    Be sure you don't have ANYTHING using the server -- Dockers, VM's, or any network users.

 

Then, if something should happen to go wrong; you can do a "New Config" -- assigning the original parity disk -- and check the "parity is already valid" box; and then you'll be right back to where you started.

 

... and BTW, run a parity check immediately after you've built the new parity disk, to provide confirmation that all went well.

 

1 hour ago, garycase said:

Yes, PROVIDING that there is NO usage of the server while you're building the new parity disk.    Be sure you don't have ANYTHING using the server -- Dockers, VM's, or any network users.

 

And this can be guaranteed merely by restarting the array in maintenance mode after replacing the parity disk, right?  I still have a couple of questions that are unanswered in bold above.  If those answers are as I think they are, I should be ready to do this.

 

 

I really appreciate all the help from all of you!

On ‎5‎/‎26‎/‎2017 at 8:04 PM, datruedave said:

It's got almost 30TB of files on it, some irreplaceable, and those that are replaceable are still cherished because my internet connection is a 1MB DSL line. 

 

While the risk you're taking with the parity disk replacement is small, it's still not zero => that's what BACKUPS are for.   Anything you consider "irreplaceable" ... or even "cherished" ... should be backed up => even if you weren't replacing your parity drive.    I know you said the "irreplaceable" stuff is backed up; but you seem pretty concerned about the "cherished" stuff as well, so you may want to rethink your backup strategy.

 

One other thought:  If you are NOT going to backup completely, you may at least want to move to a dual parity setup.    This would protect you against a drive failure during a rebuild -- i.e. if a drive fails and you replace it, the rebuild to that replacement will succeed even if another drive fails during that process.    At this point, I'd do the upgrade to a 10TB parity drive that you're planning; but then plan to add a 2nd 10TB drive as a 2nd parity so you'll have better protection of your data.

 

As for your other two questions:

=> Yes, the Main screen shows your drive assignments.

=> As for auto-starting the array ... the safest thing to do for now is simply turn off auto-start while you're "messing" with the system ... and then turn it back on later, after you're all done.

 

On ‎5‎/‎27‎/‎2017 at 1:01 AM, garycase said:

As for your other two questions:

=> Yes, the Main screen shows your drive assignments.

=> As for auto-starting the array ... the safest thing to do for now is simply turn off auto-start while you're "messing" with the system ... and then turn it back on later, after you're all done.

 

Thanks.  This has allowed me to pull the trigger.  I didn't know there was such a thing as dual parity.  I'll have to read up on that.  It was a bit shocking to see my uptime stat go from triple digit days to single digit minutes!  Looks like I'll know in about 19 hours whether I did everything correctly!

 

Thanks again for everyone's help with answering my questions!

On 5/27/2017 at 1:01 AM, garycase said:

 

 

OK, the parity rebuild is done and it's telling me parity is good.  I'm starting a parity check now before I take it out of maintenance mode.

 

One thing that didn't look right, was that it gave me an error where the Total Size should have been indicated:  Warning: parse_ini_file(state/diskload.ini): failed to open stream: No such file or directory in /usr/local/emhttp/plugins/dynamix/include/DeviceList.php on line 21 10.0 TB

 

Please tell me that I was right and that this isn't a dealbreaker.

Edited May 29, 20179 yr by datruedave

I have no idea what that line means -- one of the Linux guru's will need to comment on that [perhaps Johnnie  ].

 

But I doubt it's a significant issue.   Post a picture of your Main tab.

 

Not claiming to be a linux guru :), but the error message refers to a missing file. This has been corrected from 6.3.4 or if are running an earlier version, simply start the array. In any case not a showstopper.

Here's a screenshot of my MAIN tab:

Edited June 14, 20179 yr by datruedave

Looks fine -- as bonienl noted, that message is just because the array is in Maintenance mode.   I'd also update to the latest version (6.3.5) after the parity check completes.

 

You clearly have plenty of expansion potential now with that 10TB parity drive .    I would, however, at some point plan on adding a 2nd 10TB parity drive to give you better fault tolerance.

 

I just wanted to thank everyone who helped me with this.  My unRAID server is working like a charm.  I've already replaced my smallest, fullest drive with my old 6TB parity drive and everything is running smooth.

And I'm saving up for another 10TB drive so I can switch to dual parity in the future.  I do have a question on that, but I'll start a new thread. 

Just thought I would add one more question for the OP. Since you mentioned triple digit days of uptime, it sounds like you don't often tinker with your server. Possibly you don't check on it very often either.

 

Do you have Notifications setup so it will email you if it has any problems?

6 minutes ago, trurl said:

Just thought I would add one more question for the OP. Since you mentioned triple digit days of uptime, it sounds like you don't often tinker with your server. Possibly you don't check on it very often either.

 

Do you have Notifications setup so it will email you if it has any problems?

I didn't have notifications set up until I was updating software to prep for this parity drive upgrade.  Now it emails me more than I would like.

 

I don't tinker with it much.  I know next to nothing about linux, so I had to read tutorials and follow them word for word to get this server set up and I don't want to do anything to make it not run!  I check the server GUI every week or so to make sure the Plex plugin is up to date, but I don't do much beyond that.  I'm thinking about adding the rclone plugin and using Backblaze B2 to back up my irreplaceable photos, so it looks like that may entail dabbling with text commands (which I absolutely hate).