Newbie Setup Questions

[jamesac]

Hi All

I am thinking of moving over to freenas from OMV which although has been a good NAS system for the past couple of years. i have had some issues with it that i just cannot resolve, so i am going to give it another crack. I first used freenas in version 7 a while back and had a bad experience with zfs, (my fault but i installed freenas on a pen, installed a 2tb drive, imported the disk as zfs file system and wrote to it, i meant to copy files but moved them and the freenas box crashed) i restarted the box and the drive was gone, i took it to a data recovery company who did not have the first idea what to do with it. turns out the usb pen i used was dodgy not sure how this affected the copy process.

Anyways sorry to waffle on but i am now at the stage where i am looking at freenas again due to the support, jails etc.

so my questions are as follows

1, i have 12 x 6tb red drives and 2 spares (not used atm) my disks are just JBOD (as in no raid, Volume management and are simply added disk1 2 etc) Most of the data i have that is important to me is backed up on seperate disk, cloud spare and crashplan, anything else it would only be an inconvenience to lose. most of the disks are nearly full but with the 2 spare drives i could move some files to create 4 free drives ready to go in freenas.
now from what i understand about vdevs, pools etc what i would like to do is take a set of 4 disks, create a vdev and a pool, which would be raid 5 so 3 drives worth of space 1 parity, and have this four times, so 4 sets of 4 disks within freenas. So i have a volume 1 of the first 4 disks with 16tb or so of space, then volume 2 etc

the reason for this is so i can create the first "volume" then copy via SMB or ftp from my OMV box to the freenas box then once i have four disks emptied, repeat the process with another 4 disks to create a second "volume" (so it would be like having 4 nas boxes all doing their own disk management, but combined into a disk) i have had some drobo boxes that did something similar and created one large volume that was managed by the box, once i create the "volume" i dont want to increase it, i would just add another set of disks.

i am not up for some of the features like file duplication and encryption etc, i just use a NAS to host my media library, run PMS, sickrage, CP and transmission, Virtualbox would be nice too but not important.

i have 32gb of non ECC ram in an ASrock c2750 board. i understand some of the results with people using these boards with freenas or BSD has been mixed, i do have an I7 available and board although i would prefer to keep my low powered system as it seems to work well with multiple encodes of plex and loads of other stuff at the same time. I use all the SATA ports on the board plus a 4 x sata PCI card. 9i can look to get something 8 port if i need to use the SSDs

Will the ram be enough to work with freenas. i have some SSDs available to use for caching, i could spare an SSD for each set of 4 disks if this make things work a little better, I am not after superspeed on my network, i have 1gb all through my house and it is sufficient for what i use it for.

i am sure these questions may of been covered so apologies, but i have read some posts and they suggest multiple "sets' of disks are ok but the powerpoint slide seems to suggest not to do this and if one of your drives die in your vdev then you lose the whole drive pool (can you not have more than one drive pool?)

so to summerise, i want to

create a set of 4 disks in raid 5, create a volume called 1 for example - share this folder
replicate this setup until i have 4 sets of drives (16 drives in total) but useable space of 12 disks worth
to be clear my current NAS hosts the drives and they are full so i cannot just "start" again and build the system to how i want to do it at the beginning of this project.

thanks all in advance for any help/answers

 

[nojohnny101]

welcome back to freenas. it looks like the last time you took a stab at freenas, that was quite some versions ago and things have gotten a lot more stable.
first off, going forward make sure you are using proper term here, there is no such thing as "raid5" in freenas. it is is either mirrored, raidz1, raidz2, etc. so by you saying raid5 i'm assuming you are referring to raidz1.

now from what i understand about vdevs, pools etc what i would like to do is take a set of 4 disks, create a vdev and a pool, which would be raid 5 so 3 drives worth of space 1 parity, and have this four times, so 4 sets of 4 disks within freenas. So i have a volume 1 of the first 4 disks with 16tb or so of space, then volume 2 etc

so on that assumption, raidz1 is not a good idea if you care about your data. raidz2 is the recommended way to go for a good balance of performance and acceptable disk failure tolerance. some people even go with raidz3 because they care about their data that much. you have to ask yourself how valuable your data is and then assess the risk you want to take. also keep in mind disk redundancy is not a substitute for good backups. sounds like you already know this but i just wanted to state it again. so what you are suggesting is not good because if you build 4 "4tb x 4 raidz1" that would mean that if more than one disk would fail in any of those vdevs, you lose everything (your entire pool). for example. let's say you have:
vdev A (4 x 6tb radz1)
vdev B (4 x 6tb radz1)
vdev C (4 x 6tb radz1)
vdev D (4 x 6tb radz1)

if you have one disk die or have any time of failure in vdev A, and then you have another disk fail in vdev D before you can replace the drive in vdev A, you lose all your data in all the vdevs. Does that make sense? Keep in mind, the reason radiz1 is not recommended is there is a good chance (or higher than one would think) that a 2nd drive is going to fail during the re-silvering process (where you put in your new disk drive to replace the failed one, and the system starts rebuilding the data). another disk can easily through read errors that might have gotten undetected or not known up as a hardware failure and then boom, there is the 2nd disk failure and your data is toast. that is why raidz1 is a bad idea.

for your situation, i would recommend 2 x "8 x 6tb radiz2". this would give you adequate drive failure protection and keep your IOPS up. doesn't sound like you have a heavy use case anyways (no VMs) so that would be plenty. or you could just do 2 x "6 x 6tb raidz2" and keep 2 spares. you can weight the benefits and drawbacks. are you able to offload the data to create this though? what is the raw size of your current data?

i am not up for some of the features like file duplication and encryption etc,

unless you specifically need encryption, it is not recommended to encrypt your drives, it can cause all sorts of problems with importing/exporting pools and recovering data.

i have 32gb of non ECC ram in an ASrock c2750 board.

i have the ASRock c2550 and it is a great little board. from what you describe, the c2750 can easily handle the plex, shares, and everything else. when one starts demanding VMs and things like that, the board struggles a bit but for most, it is a very capable and efficient board. the freenas mini the xisystems sells actually uses this board! the only problem is the non-ECC ram. for piece of mind, you really should be running ECC. ZFS is highly dependent on RAM and having non-ECC RAM opens you up to single bit corruption and other problems. if one of those happen, your screwed and will be kicking yourself that you didn't spend the little extra money for peace of mind. also for sizing sake, the general rule of thumb is for every 1TB of storage, you have should have 1GB of ECC ram. that would probably put you right around 64gb.

good luck!

 

[jamesac]

Hi thanks for that reply, understood about raid 5 etc

My data on a scale of 1-10 value - i would say 5 as its blu ray rips and movies/tv which i can get again but it means having to repopulate the drives which will take a long time...! anything of value is backed up elsewhere but still available on my nas

my total used data on my current box is 61tb so i dont have much room for using 8 drives in an initial VDEV of 8 disks in RAIDZ2 config (which is like raid 6 yes?) (about 10tb is backed up and i do have externals and loads of 2/3/4tb drives around to move data but maybe not enough for a whole 4 disks

but my question to this was that i can or cannot have more than one pool, so for example, VDEV1 4 disks in RAIDZ1 config, if one disk dies replace, if two disks die i lose the 4 disks of data but that only affects pool 1, pool 2, 3 and 4 are nothing to do with each other and show up as four seperate volumes within freenas?

i also would like to expand the number of drives in the future so im concerned about this 64gb limit as ram doesnt exist higher for my board yet nor is supported i dont thnk (at time of purchase anyways)

 

[BigDave]

but my question to this was that i can or cannot have more than one pool

You can have multiple pools.

for example, VDEV1 4 disks in RAIDZ1 config, if one disk dies replace, if two disks die i lose the 4 disks of data but that only affects pool 1, pool 2, 3 and 4 are nothing to do with each other and show up as four seperate volumes within freenas?

You can do this, HOWEVER, as the other posters in this thread have cautioned you, using RAIDz1 is fool hardy for the following reason.
The shear size of the 6TB hard disk means doing a re-silver of a failed drive will take DAYS to complete, this increases the chance
of a second drive failure exponentially! The re-silvering process is HARD on your drives, and using RAIDz1 with these big monster
capacities is a recipe for disaster. You have been warned Sir!