File Corruption, help or advice please...

I have two drobo mk2’s daisychained via firewire to my mac mini (2010) and recently had the following failure…

Using Plex software to play a MKV video file, Plex reported that the (previously working) file was corrupted, no other player would access it either, other files were ok.

I posted this on the Plex forum and it seems that if you try to play a file when the drobo has spun down, it will allow the system access BEFORE the disk has fully spun up, this then fails and the system marks the file as bad. A reboot of the server seems to fix it as does unmounting and remounting the drobo.

Is this possible?

Is there a way to stop the Drobo spinning down??

The file was copied before the reboot and is indeed corrupt although exactly the same size as a good copy - the header info is partially missing.

Any ideas???


You might be able to go into drobo-dashboard, under options, and (at least from my experience) there is a slider bar of “how long” to spindown the drives, slide it far right to go to “never” so then they will stay at speed all day long.

Alternatively, your mac might be being too “impatient” ; If you prefer to keep the drobo “power conscious” then maybe there is a way to adjust the properties of that particular device through the mac control panel to “have a longer timeout before fail” or somewhat.

I can possibly imagine that the corrupted header info was the mac not waiting for the full cycle of the drobo commanded to “wake” followed by the average spinup of the disks inside, by the time that drobo identifies and quick-validates the drives as not having been moved, removed, or otherwise, and then the drobo responding to the MacOS “Yep, alls good here, now what did you want me to do again?”

that last bit was somewhat sarcastic; lol

Hopefully your drobo 5d (or mac control panel under “drive power management”?) can adjust the power down slider to “never” which hopefully will solve (future) problems.

Do you still have a backup copy of the MKV? As in, that one might be already “toast” but if you delete the corrupted one from the Mac’s perspective and then copy over a known-good one, and even try playing via alternative video player, then hopefully you’ll have better luck.

Let us know if this helps or works out as you hope.

These are both four bay drobo’s and there are no spin-down options in dashboard. Mac control panel has turn off hard disks when possible set to off.

I have replaced the file and it now works, just trying to find a way to ensure it does not happen again.

Is it perhaps a power management trigger from the firewire bus?

I’m not as familiar with the older generation drobos but thought I’d at least try to help ya.

Best of luck

Thanks for the help zepcom, but I can’t find any way of forcing the drobo to stay awake.

Apart from a little script that reads the disk avert couple of minutes, but not sure I like that idea.

I used this for my Drobo (v2)

Had this fault again tonight.

Server was asleep, woke it up and went to watch a film, got the error message saying it can’t read the file again.

This time I ejected the drobo, re-mounted it and the film played normally.

Anyone know why this should happen?

hi dave,
do you have another way to connect the drobo’s to your computer (assuming mac) without daisychaining?

also it might be a good idea to try a test on a few of your movie files to put them into read-only property.
(often a player software (usually media player) will “change” the content of the file in some way, and maybe that is what is corrupting things).

usually its meta tags/mp3 tags which get updated or cleared but it could also be daisy chaining.

I could possibly switch to USB connection.

The software i am running does not use file metadata, i am assured that it does not alter the files in any way by the writers of the software.

It only ever happens if the server is asleep and woken to play a film in rapid succession i.e within a few minutes of wake -> play.

Tried USB yesterday, It played one film ok, then i let the server sleep, upon waking it up it played a bit of another film then the drobo ejected itself resulting in the “This disk was not ejected properly…” error message.

So it looks like USB is not the way to go.

Any more suggestions??

hmm, for the drive ejected message, am not sure, but for the plex, try making one of your smaller source folders read only.
(if plex interprets connection errors as “corruption”, it might not help at all, but if plex detects “changes made by other non-plex programs accessing and/or modifying your source files” then it might :)[hr]
it might also be worth updating your plex forum post to ask if the makers of plex can add a feature to help prevent this problem.
maybe theres a way for plex to handle the error in a better way, such as increasing a timeout or something to allow the file to be accessed and buffered

Well, I’ve stuck it back on FireWire so no more ejections.

Had the error again yesterday, remount and all is fixed. It definately is related to the OS because once Plex has discovered the file problem, the film will not play with any other software at all, it seems the OS marks it as bad and a remount clears the error???

It only happens on the drobo too, not the local drive.

hmm, well it could just be “mac os”… i dont mean to sound bad but almost all issues for normal running seems to be macs or not using usb :slight_smile:

but seriously though, have you looked into what mgriffin mentioned - maybe that might help?