NAS104 Raid decision? Xraid vs Raid 10 etc #24296869

StephenB wrote:

Your 20 hour RAID-10 initialization seems more typical. I've gotten about 12 hours when I've replaced a 3 TB drive in my pro-6. I haven't initialized with RAID-6 - in principle the RAID mode shouldn't matter much, since the two parity blocks are always the same, so they don't need to be recomputed. Though if they are computed over and over, it likely will take somewhat longer. Note that RAID initialization requires all sectors in the volume to either to read or written (even if they are not in use). XRAID is standard RAID-1 or RAID-5 (if disks are different sizes, then some layers are RAID-5 and others are RAID-1). So optimizing XRAID means optimizing both those modes. RAID-6 isn't a gimmick, and there are netgear folks here (mdgm for one) who frequently recommend it. Though usually folks are using it on x86 platforms like the ultra, pro, RN300 or RN500. Initialization is rare, the benchmark afterwords is more useful for understanding performance. On the performance side, the write penalty in the original review was mostly due to the btrfs copy-on-write. That increases data safefy. Otherwise write speeds for RAID-1 should be about the same as read speeds.

I understand that an actual rebuild after a failure is a very different and intense process. I don't understand why the initialization should take any longer than a full format.

I know it isn't a gimmick, I just mean their implementation is not good enough to merit it's use.

StephenB wrote:
What did you see with RAID-10 btw?

Well I was going to wait until I had more data on the other modes, but here it is. Pretty embarrassing performance.

Just to reiterate I am using a NAS104 with 4 3TB Western Digital Red drives. I first updated my firmware to 6.2 before I did anything.
I am using no encryption and no anti-virus.
I am using a wired connection via a 100mb switch that both the computer and drive is plugged into with nothing in between. I am testing using a windows file write on a mapped network drive of a share. This is raid 10. I tried with 3 different file sizes. Pretty consistently bad.

NAS performance tester 1.7 http://www.808.dk/?nastester
Running warmup...
Running a 100MB file write on Z: 3 times...
Iteration 1: 11.79 MB/sec
Iteration 2: 11.78 MB/sec
Iteration 3: 11.80 MB/sec
-----------------------------
Average (W): 11.79 MB/sec
-----------------------------
Running a 100MB file read on Z: 3 times...
Iteration 1: 11.73 MB/sec
Iteration 2: 11.82 MB/sec
Iteration 3: 11.84 MB/sec
-----------------------------
Average (R): 11.80 MB/sec
-----------------------------
Running warmup...
Running a 400MB file write on Z: 3 times...
Iteration 1: 11.84 MB/sec
Iteration 2: 11.81 MB/sec
Iteration 3: 11.82 MB/sec
-----------------------------
Average (W): 11.82 MB/sec
-----------------------------
Running a 400MB file read on Z: 3 times...
Iteration 1: 11.75 MB/sec
Iteration 2: 11.82 MB/sec
Iteration 3: 11.84 MB/sec
-----------------------------
Average (R): 11.80 MB/sec
-----------------------------
Running warmup...
Running a 2000MB file write on Z: 3 times...
Iteration 1: 11.81 MB/sec
Iteration 2: 11.81 MB/sec
Iteration 3: 11.81 MB/sec
-----------------------------
Average (W): 11.81 MB/sec
-----------------------------
Running a 2000MB file read on Z: 3 times...
Iteration 1: 11.82 MB/sec
Iteration 2: 11.77 MB/sec
Iteration 3: 11.78 MB/sec
-----------------------------
Average (R): 11.79 MB/sec
-----------------------------