The original ZFS machine has grown a bit over the years. It started with two 2TB hard drives, then got two more, then finally two more. The “little” NZXT case has more than enough drive slots, but this setup violated one of my two rules for storage systems:
“Da Rules”:
- Just because a case has N drive bays does not mean it has enough cooling for N drive bays
- RAID5 is not enough
These two rules were a result of stuffing 6 drives in a nice Lian-Li aluminum case that had a 6-bay internal cage (these events predate this recorded history). One day, it lost a drive. After replacement, but during the re-silvering, it lost a second drive. And thus the entire array was gone. The first drive may or may not have been lost to heat. The second drive was definitely lost to heat.
The ZFS machine addressed rule #2 by having drives in a mirror and using active scrubs. The active scrubs make sure that both drives have a readable copy of each sector. So, when a disk is lost, you are reasonably sure the re-silver will has something valid to read. This machine has lost 2 drives (not at the same time). Yes, re-silvering was stressful.
To address rule #1, my ZFS machine finally gets the case it deserved in the first place: a Rosewill RSV-L4500 – 4U. At $116, this case has 15 drive slots and 8 fans. The three-sets-of-five bays lets me install the drives with an air gap of one drive between any two drives.
Here are the smartctl temperatures before and after:
| Drive | NZXT case | Rosewill Case (immediate/24hrs) | |
|---|---|---|---|
| 1 | 43 | 31/32 | |
| 2 | 42 | 31/32 | |
| 3 | 35 | 33/33 | |
| 4 | 36 | 34/34 | |
| 5 | 37 | 34/32 | |
| 6 | 35 | 35/33 |
Drives #3 and #4 are the original, “babied” WD 2TB black drives. What little cooling existed in the NZXT, these drives got, so there was not much movement in temperature.