Having set up my zpool, datasets and shares, I've taken a look at monitoring my disks...
I've set up mail, so the system can send me mails. But I understand that monitoring the disks more closely is a good idea. For this I should use S.M.A.R.T.
My systems a 24drive SuperMicro SC846 Xeon E5520 2,25GHz 12Gb ECC RAM with a 3Ware RAID controller. All disks are in JBOD mode.
As a former 3ware RAID controller user(I upgraded and had no use for the 3ware anymore) let me ask you these questions. When you have the answers you will be able to decide for yourself how important thing are. No, I can't provide the answers for you because just because my 3ware controller worked doesn't tell me if yours will. It is also about how much risk you are willing to take. I am very conservative and do not like to take much risk at all. Other people are completely okay with taking very large risks.
Will smart testing and polling be possible behind a JBOD configuration?
Does your 3ware controller work with smartctl and have you tried to monitor a disk in FreeNAS? Have you tried to do a SMART test in FreeNAS?
And would it be necessary? Doesn't the controller monitor this? I suppose it would start flashing red on the LED in the drive-bay?
Does the manual for your card say it will monitor it? If so, what is the 'threshold' for deciding a drive is bad? Is it a single read or write error or only when a drive disconnects itself from the controller?
I also read somewhere on this forum that ZFS monitors the disks, would this turn up in the daily mails (the standard ones) - and would, if the controller marks a disk as dead/bad, it be added to the daily report?
You should get daily emails, but you should definitely test it by using a failed disk or disconnecting a disk while the system is on and see if you get an email that says that the disk is bad.
FreeNAS is nothing more than a pretty UI for FreeBSD. As such, it does try to do a lot of things that the server admin would normally do entirely from the command line. So you should definitely validate any assumptions with your hardware before you trust that you'd get an email if "something were wrong". Plenty of people seem to think that they'll get a warning light, a buzzer on their speaker, an email, etc but didn't try to validate anything.
Hint: if you don't setup the email function you shouldn't ever expect FreeNAS to email you(yes.. prior admins HAVE been that dumb and even admitted to it in their threads asking for mercy from the ZFS data gods). /hangsheadindisgust
Bottom line, you are asking very good questions. You should take the time to validate that all of this stuff really works for you before you start relying on it to store your data safely. I know that it will be time consuming. But your data depends on you knowing how the system is supposed to work and making sure you know how and when you should get warnings if things start going bad. If you are like most people you have done almost everything in Windows and are just starting to dabble outside of the Windows World(that was me 18 months ago). It's going to be a slow and steep learning curve. Remember back to when you first started learning about Windows/DOS. It was very slow to figure stuff out and you had lots of questions and darn few answers. If you aren't ready to take the time to do it right one of two things will happen:
1. You'll get very lucky and not lose your data.
2. You'll lose your data(hopefully you'll have good backups).
More often than not it seems people fall into #2 because they heard about FreeNAS on Thursday and wanted the server up and running by Sunday.
Data on a zpool cannot be recovered with any "recovery tools" I'm familiar with so if poor management on your part leads to an unmountable pool you are going to be very unhappy with the results. One recovery company was quoted as saying that they would attempt recovery for a flat $15000 per month for 40 man-hours per week of labor but there was no guarantee of any data ever being recovered. So keep that in mind when you start assuming things should work a particular way and if you want to take the time to verify they work or not.
