Question NAS Noob, tips on first serious RAID

[mikeford]

I've had some kind of network storage for more than a decade, first half of which was littered with various minor to major issues and failure, cheap Lenovo IX2 jbod 6TB 24/7 without a hitch for last 5 years. Since they are dirt cheap on clearance I bought a second IX2 jbod 2TB, which is currently a mirror of the measly 1 TB of data on first IX2. I just never got around to moving much to the NAS from my daily use/media PC which has about 10TB of drives, using I suspect a bit less than 6TB due to again most of the content duplicated on one or more of the 4 drives.

I am about to make the jump to a "real" RAID by adding a Lenovo PX4-400D, $150 for new old stock, 30 day warranty diskless (long thread in hot deals with details). Old hardware, but new, and true business class features and build quality, tested by users here to accept up to 4x 8TB drives. The idea is to setup the PX4 with a large enough raid array that it will hold all of potential near term files and survive at least a single drive failure. At least one of the IX2 would stay JBOD with enough storage to mirror the PX4, but most of the time be offline and turned off, maybe even rotate use of the two IX2, or use one for full backup and one for partials on a more frequent basis.

Which drives?
I have 3x WD Red 3TB, and 2 or 3 Seagate NAS grade 2TB drives in my main PC or laying around, intending to end up with the PC using a small SSD and 1x HD, so "some" of the drives can end up reused in some of the NAS units, as well as possibly moving existing NAS drives into the PX4 (4x 3TB for 9TB of RAID maybe). Sooner or later I do expect to migrate to 4 or 8TB as needed in the NAS family. If any issues turn up with using existing drives, then I'll go immediately to 3x or 4x 4TB for the PX4.

Any issues with buying refurbs, most of concern is if a drive fails later on its practical to replace same model etc.

24/7 or timed spin down?
This is for a home with 3x users, but many times not even accessed every day or just a few times a day. Factory setting is 24/7, one of the IX2 now set to 1 hr spin down.

 

[aigomorla]

4x 3TB for 9TB of RAID maybe

Please tell me this is not on RAID-5 settings...
RAID 5 has horrible URE odds on spinners, and is not recommended at all unless its on SSD's.

Any issues with buying refurbs, most of concern is if a drive fails later on its practical to replace same model etc.

I usually buy 2 refurbs, and have one as backup after i check smart on it and do some light transfers to see if the drive is good or not.
But i have no issues with running refurbs as long as my array has some form of fault tolerance.

 

[mikeford]

I haven't decided, but was looking at Raid 5, doesn't look like any of the NAS from Lenovo support Raid 6, and the other Raid modes seem less practical than JBOD. The real killer which I wasn't aware of is the URE, unrecoverable read error, and that on most Raid it totally prevents rebuilding the array, total data loss. Maybe Raid 5 made sense back in the day when drive sizes were in MB, but doesn't seem to anymore.

OTOH maybe way to look at it is how often will one drive hard fail in an array of 4 in a Raid 5?

What action would I take if such a failure occurred. If I followed my stated practice of running off the 4x drive Raid 5 NAS, daily incremental backups to a JBOD IX2, and periodic full backups to a normally offline and powered off JBOD NAS.

Thinking about it awhile more I guess. As it is now I have a SSD C, and 3x 3TB D/E/F drives with files scattered and duplicated across all three including mirrors of previous NAS. My 5 year old IX2 with 6TB has less than a TB on it due to lazy and undecided, and the new IX2 with 2TB is a mirror of the old one. Not very efficient, but oddly reliant.

 

[Muadib]

Double

 

[Muadib]

Please tell me this is not on RAID-5 settings...
RAID 5 has horrible URE odds on spinners, and is not recommended at all unless its on SSD's.

I didn't know this. I'm using raid 5 on my 4 drives in my NAS. What is recommended?

 

[aigomorla]

I didn't know this. I'm using raid 5 on my 4 drives in my NAS. What is recommended?

RAID 6 if your system can support it.
RAID 10 if not, but you lose half your space.

Otherwise Raid-Z and get off NTSF entirely.

OTOH maybe way to look at it is how often will one drive hard fail in an array of 4 in a Raid 5?

Its all on lottery.
But the whole point in having Raid is for fault tolerance.
Its really obnoxiously painfully long rebuilding a RAID 5 array with spinners and high cap drives.

 

[sao123]

Isnt the whole Raid-5 + URE thing a bit overblown? I have seen rebuttal arguments that raid-5 is fine for home use small NAS's because newer drives are now URE in 10^15 or 10^16 instead of the 10^14 previously calculated.

Why RAID5 and RAID6 still work in 2019 and beyond - High-Rely

RAID5 and RAID6 still work. Google “RAID5” and you’ll quickly find articles that warn you never to use it. The claim is RAID5 won’t protect your data and is doomed to failure. People even claim RAID6 (which protects against 2 drives failing) is dangerous. We’re here to tell you that for...

www.high-rely.com

RAID 5 is perfectly fine for home usage

louwrentius.com

 

[aigomorla]

Isnt the whole Raid-5 + URE thing a bit overblown?

no its not.. because of also the rebuild time involved in rebuilding a raid-5 array using large spinners.

It ends up putting more stress on you when you restore the array should you have a failed drive, as it can take days for even a 4TB drive to rebuild its array. Now imagine how many hagan daz ice cream snacks you could of had in the time involved to restore an array on a 8TB or greater.

That is why it just makes no sense to do a RAID-5.
It might honestly even be faster to back up your data, and rebuild the raid 5 array from scratch from a disk loss, then rebuilding the array via controller by disk replacement.

 

[Muadib]

no its not.. because of also the rebuild time involved in rebuilding a raid-5 array using large spinners.

It ends up putting more stress on you when you restore the array should you have a failed drive, as it can take days for even a 4TB drive to rebuild its array. Now imagine how many hagan daz ice cream snacks you could of had in the time involved to restore an array on a 8TB or greater.

That is why it just makes no sense to do a RAID-5.
It might honestly even be faster to back up your data, and rebuild the raid 5 array from scratch from a disk loss, then rebuilding the array via controller by disk replacement.

I replaced my 4 4TB drives for 4 16TB drives in a RAID-5, and yes, it took days to do, but I didn't lose data. Are you saying not to use RAID-5 because of the time it will take to recover from a drive loss? I didn't go RAID-6 because of the space I would lose. Maybe when I go with 8 drives I'll reaccess.