[Feature Request] Make Array Read only..

[jbuszkie]

I'd like to see an easy way to make the array read only..  Solely for the times when I'm upgrading parity.  Right now, I believe the procedure is to

not write to the array so your old parity is still valid.  I did this by going into maintenance mode.  I'd love an option to make the array RO so files can still be read...  but no write will occur...  One step further would be to allow new files to be written to the cache drive.. but not moved to the array until you made the array normal RW again.

 

Is there a way to do this already?

 

And sorry if this has already been suggested..

 

Jim

[Squid]

You could make all of your shares either private or secure, and then set the permissions to be read only.

 

Not quite a 1 step process, but it should accomplish what you want.

[garycase]

I'd like to see an easy way to make the array read only..  Solely for the times when I'm upgrading parity.

 

I don't see much need for this.

 

It's pretty simple to just not write to the array while you're doing a parity upgrade 

[And in fact, it's actually okay to write to it anyway ... it slows down the new sync a bit, but everything should work just fine.]

 

If you're referring to the writes from any active Dockers, VM's, etc. => you can simply temporarily disable/shut down those while you're doing the upgrade.

 

The reason you're referring to (so your old parity is still valid) is so that if a drive during the new sync was to fail you could do a New Config with the old parity drive and still recover the data from the failed drive.  Note that while conceptually this is true, at the moment it wouldn't work, because the "Trust Parity" option invokes an immediate parity check when the array is first started, and this can effectively invalidate your old parity drive because any bad sectors on the failed drive will cause invalid "corrections" on the parity drive if they're in the first part of the drive -- i.e. they may be done before you can CANCEL that check.    Hopefully this will be fixed SOON (I've asked for it several times).

 

But IF the "Trust Parity" option is fixed so it truly TRUSTS parity, then indeed it would be prudent to disable all Dockers and VMs before upgrading parity; and then not doing any writes during the new sync, so that you indeed had the ability to recover any drive that may fail during the process.

 

 

[jbuszkie]

It's pretty simple to just not write to the array while you're doing a parity upgrade 

Not really..  I have automatic backups that occur every night.  I'd rather not have to remember to disable them... only to forget to enable them again.

 

The reason you're referring to (so your old parity is still valid) is so that if a drive during the new sync was to fail you could do a New Config with the old parity drive and still recover the data from the failed drive.  Note that while conceptually this is true, at the moment it wouldn't work, because the "Trust Parity" option invokes an immediate parity check when the array is first started, and this can effectively invalidate your old parity drive because any bad sectors on the failed drive will cause invalid "corrections" on the parity drive if they're in the first part of the drive -- i.e. they may be done before you can CANCEL that check.    Hopefully this will be fixed SOON (I've asked for it several times).

Yes this is what I'm referring to..    And I do know of the auto party sync when trust parity thing is invoked.  But isn't the old way still valid with the setinvalid slot thing? Couldn't that still be used to recover the failed disk?

 

Jim

[garycase]

... But isn't the old way still valid with the setinvalid slot thing? Couldn't that still be used to recover the failed disk?

 

Yes, you're correct.    As long as you've saved the contents of the flash drive BEFORE you do the upgrade, you can restore the previous content and set an invalid slot and do the rebuild.

 

[jbuszkie]

Ah...  I didn't save the old config..  I guess That is necessary to this.  I'll have to remember that if I want to put my 4T back a parity to test the speed and be covered...

[nick5429]

I don't see much need for this.

 

It's pretty simple to just not write to the array while you're doing a parity upgrade 

 

I strongly disagree.

 

The lack of a true 'read-only' mode completely prevents you from being able to fall back on the "old" parity drive to avoid data loss if a 2nd drive fails during the upgrade.  With the currently implementation, there are lower-level filesystem operations that issue writes to the disk, regardless of whether any user process or action has written to the filesystem