Drive letters keep changing - ?

[andyptak]

I have a couple of external boxes, each with 8 JBOD disks in them. One box and its disks are synched to the other. This is my production backup.

Each time I turn the machine on, some of the drive letters have changed and sometimes one or two of them have lost a drive letter altogether. It's a real PITA to fix it every time I use it. I'm also concerned that the synch software will become confused and make a mess of everything - it usually says it can't find the drives and therefore, cant synch.

Anyone have an idea what's going on? Thanks.

[scyth]

>  It's a real PITA to fix it every time I use it.

and how do you fix it, may be that shed some light or lead to alternative solutions ? through "computer management" -> "disk management" ?

[Eric Myrvaagnes]

It sounds to me like an operating system problem, Andy. Are you on some version of Windows?
If so, you should be able to specify that your selected drive letter should always be used. If you don't, Windows assigns drive letters from available ones in the order the drives are encountered.

I can't find this in Windows 10 at the moment, but I know I've done this numerous times in the past on previous versions of Windows.
Perhaps googling something like "How to lock Windows drive letters" might get you some info.

[E.J. Peiker]

It's very simple to fix this, go into Disk Management under Computer Management, right click on the volume you want to change and select "Change Drive Letter and Path" and assign it a discrete drive letter rather than letting the computer auto-assign letters which it does in the order of which they connect and isn't always the same every time.

If you want to use a letter that's already assign, temporarily reassign the drive that is using that letter to something else...

[andyptak]

Thanks guys. I've already done that through Disk Management in Windows 8 and it still keeps happening. Puzzles me.

[E.J. Peiker]

Thanks guys. I've already done that through Disk Management in Windows 8 and it still keeps happening. Puzzles me.

Have you done it for EVERY drive?  If not, if a drive loads before an assigned letter drives there is a conflict and the assigned letter won't be given to the drive you want.  You need to do this for every drive that ever attaches to your computer, even any card readers, for it to stay consistent.

[andyptak]

Yep - every drive.

[E.J. Peiker]

Yep - every drive.

That makes absolutely no sense but hard to diagnose without sitting at your computer

[andyptak]

I agree.

The only thing that I have thought of is that I attach a portable drive to it when I am adding new material and therefore, that drive is assigned a letter - but the other drives are already spinning by then and shouldn't get bumped out of the line, should they?

[E.J. Peiker]

Reassign a drive letter like X or Y or Z to the portable drive and then that may stop happening.

[FabienP]

The only cases where I have seen this behaviour is when Windows does not recognise that the hardware has already been plugged in once and assigns a new letter. This could happen if another USB port is used or the firmware of the external storage unit was updated since the last time. Or when a controller is acting as a middleman between the OS and the disks.

Are the disks directly presented to the operating system (since you say it is JBOD) or does some black magic occur in the enclosure holding the disks? In the latter case, this could be a hardware specific issue. Having a look at support options provided by the manufacturer might help.

In any case, a workaround exists for sync applications which work independently from drive letters: instead of indicating a path with drive letters, use the serial number of the disk or the disk label, which do not change every time the volume is mounted. Such sync applications include SyncBack or FreeFileSync but I am sure many more applications support this as well.

Cheers,

Fabien

[andyptak]

Good idea Fabien, unfortunately my software doesn't support that. I use Goodsync.

I have 24TB of data and to switch to another software would probably tie up my machine for a week or two while it gets in sync - again!

Thanks anyway. Good try.

[scyth]

Thanks guys. I've already done that through Disk Management in Windows 8 and it still keeps happening. Puzzles me.

may be try to use a script @ start-up = https://technet.microsoft.com/en-us/library/cc766465(v=ws.10).aspx

or, for example, use wmic (wmic volume get...) & mountvol in a batch file to find where (letter) the disk with a particular label mounted (in batch file, assuming the label is "JBOD" set jbod to whatever letter is under : for /f %%D in ('wmic volume get DriveLetter^, Label ^| find "JBOD"') do set jbod=%%D), find it's volume name and remount to the proper letter

[andyptak]

Thanks, but this is way above my head.

[Joe Towner]

What if you shift from drive letters to mount points?  Sync still works the same but instead of f:\ g:\ h:\ i:\ you set it up as c:\mnt\f\ c:\mnt\g c:\mnt\h etc...

[andyptak]

Thanks Joe. Again, a bit above my head.

The only option given is:

1. Drive letter
2. Folder on that drive.

It must be a folder on a drive for the command to be accepted.

That goes for both source and destination.

[Joe Towner]

Thanks Joe. Again, a bit above my head.

The only option given is:

1. Drive letter
2. Folder on that drive.

It must be a folder on a drive for the command to be accepted.

That goes for both source and destination.

So what you can do:

Go to file explorer, go to the root of the c:\ drive and create a folder, call it 'externals'.  Next, type in 'diskmgmt.msc' in the search and go to Disk management.  For each of the external drives, right click the partition, and hit 'change drive letter or path'.  Instead of assigning it a drive letter, assign it a path under the c:\externals folder - ideally what ever you would name the disks.  Do this for all the external disks.  Then you should be able to set GoodSync to the respective folders and be good to go without any changing letters.

-Joe