how to achieve best redundancy ?

[anorphirith]

Hello,
I'm looking to make a NAS with 6 HDD's
My motherboard supports 6 SATA and I want to use all 6 in the array = I don't have the option to loose a disk for freeNAS only.

Installing freenas on a USB stick would probably not be fast enough to manage 12tb or more of data = I was wondering if I could intall freenas on a pre-made (as in made before installing freenas) partition of a hard drive.

And if that's possible, I could duplicate that set-up on each of the 6 hard drives; so that if the hard drive that fails and is the boot harddrive, the NAS would automatically boot on the next working hard drive.

 

[starryganesh]

Err, why do you think a USB stick would not be fast enough? You can easily get 30MB/s read/write on USB2 which is plenty fast enough for anything the operating system is going to need to take care of. Most modern motherboards have USB3 ports as well so if you get a USB3 flash drive the I/O will be even faster.

 

[RvdKraats]

The OS is only loaded at boottime, and runs from memory from then on. I don't think USB speed would be of any concern.

 

[anorphirith]

thank you for the replies, what if the usb fails, my primary concern is redundancy

 

[starryganesh]

Buy a USB with good reputation, not just the cheapest one you can find. I really doubt the USB would fail but if it does there's nothing you can do to mitigate the damage with your current setup.

 

[ben]

Keep an up-to-date copy of your config database on hand. To shave a few minutes off recovery time, do that, then make another whole boot USB, upload the config to that, and import the pool there. That way if the one you're using dies, you can swap the other pre-made one over and import the pool back to it, bringing you back up to operation. Remember, ZFS pools don't care about what happens to the boot drive - even if you do neither of those things you'll be able to make a new boot USB and re-import the pool (at which point you'll have to reproduce your config by hand). It would take an extreme event to break the boot USB AND render the data on the disks inaccessible - and having a boot partition on each disk would not save you from something like that.

 

[cyberjock]

Buy a USB with good reputation, not just the cheapest one you can find. I really doubt the USB would fail but if it does there's nothing you can do to mitigate the damage with your current setup.

Yes there is. Backup your config file. I've got threads around where I wrote scripts to backup the script every night automatically.

Your USB stick goes bad and all you do is:
1. Reinstall FreeNAS to new USB stick.
2. Import your config file and wait for reboot.
3. Done!

I really am shocked that people think that FreeNAS doesn't have a good recovery plan for USB failure for a system sold to corporations. It's been mentioned in the forum regularly, its in the manual, and its in the FAQ.

 

[anorphirith]

how about having two USB drives attached so that if one of them dies the other one can take over. if I have the bios set on boot from USB then it can automatically boot from the working USB drive ?

 

[cyberjock]

Not sure how you'd even do that. If the USB stick goes bad it'll probably still try to boot then fail and your system has no way of knowing that the USB is bad.

 

[anorphirith]

Yes there is. Backup your config file. I've got threads around where I wrote scripts to backup the script every night automatically.

Your USB stick goes bad and all you do is:
1. Reinstall FreeNAS to new USB stick.
2. Import your config file and wait for reboot.
3. Done!

I really am shocked that people think that FreeNAS doesn't have a good recovery plan for USB failure for a system sold to corporations. It's been mentioned in the forum regularly, its in the manual, and its in the FAQ.

where do you do your backup ? on the raid array itself ?

 

[fracai]

Err, why do you think a USB stick would not be fast enough? You can easily get 30MB/s read/write on USB2 which is plenty fast enough for anything the operating system is going to need to take care of. Most modern motherboards have USB3 ports as well so if you get a USB3 flash drive the I/O will be even faster.

Note that USB3 is disabled by default in FreeNAS and you may experience problems with it enabled. After building my system with it enabled (XHCI) I get an interrupt storm whenever any USB device is plugged in. I haven't experimented with this to determine if the OS drive causes these, or to generate any logging dat for submitting a bug, but it was 100% repeatable for my system that plugging in a USB device with it enabled caused the storm.

Plus, USB3 isn't likely to get you much extra for thumb drives anyway. And the drive is only read at boot, so putting much into this one area really isn't worth the effort.

 

[ben]

where do you do your backup ? on the raid array itself ?

No. That's like saying the safest place to write down the combination to a safe is on a piece of paper inside the safe itself. Keep it on whatever computer you'll be using to administer FreeNAS, and at least one other place (like a personal USB drive) as well.

 

[cyberjock]

No. That's like saying the safest place to write down the combination to a safe is on a piece of paper inside the safe itself. Keep it on whatever computer you'll be using to administer FreeNAS, and at least one other place (like a personal USB drive) as well.

My script does backup to the zpool itself, but it is also backed up elsewhere. So yes, it is on the zpool. But yes, it is on the computer I administer FreeNAS with. :)

But I don't consider a backup to the zpool a bad thing. If you don't backup your zpool and you lose your zpool you won't give a crap about your config. You'll be too busy thinking about all of the stuff you lost. If you do backup your zpool all you have to do is go to your backup server and copy the config file off that

 

[ben]

Well that's assuming people actually back up their main zpool to somewhere else ;)

 

[FireWire2]

anorphirith
There are TWO things that you need to consider to make your freeNAS --> resilient
1_ Back your system configuration ANY time you make a change and save it somewhere else, but not in the NAS itself.
2_ Data volume in a redundant mode: such as RAID1/10/3/5/6/ or ZFS. Schedule fschk weekly or monthly on the data volume.
This is very important: W/o it your system can have a dirty bit and will lead to corruption
3_ Have another cheap near-line backup like BIG/SPAN volume in other system (Optional but recommend)

Like other post stated with back file restore the system pretty easy. You can have TWO USB OS... just have extra ONE inside the box as inventory and replace the bad USB when need.

My 40TB system does not use ZFS but hardware raid, it'd running over 3yrs without hiccup, after i schedules the fschk cron job. I almost lost my data due to dirty bit.
BTW i do not have the option 3

 

[cyberjock]

My 40TB system does not use ZFS but hardware raid, it'd running over 3yrs without hiccup, after i schedules the fschk cron job. I almost lost my data due to dirty bit.
BTW i do not have the option 3

I'm sorry, what!? fschk doesn't work on ZFS.. at all. And ZFS isn't something mutually exclusive of hardware RAID. You can do ZFS on a hardware RAID, but its strongly recommended against it because you lose the self-healing characteristics of ZFS. Are you talking about UFS? UFS doesn't have any checksumming of the file system or the files, so a single bit error due to bit-rot can spell disaster for your entire hardware RAID array. This is why I recently bailed on Windows Servers and switched to FreeNAS with ZFS.

ZFS is superior with regards to file system and file content reliability because of the checksuming. A dirty bit won't spell disaster for you like UFS(or even FAT32 or NTFS) because of the checksuming & parity.