Sandisk Lightning power modes

[rthorntn]

Hi,

Is anyone familiar with these drives, I have some LB1606R and I'm trying to figure out if I can put them into standby to save power, some posts over on the UNRAID forums provide the following info, I tried this but as you can see it doesn't seem to work (it should show additional sense info).

$ sudo sg_start -vvv --pc=3 /dev/sg1
open /dev/sg1 with flags=0x802
    start stop unit command: 1b 00 00 00 30 00
      duration=8 ms
$ sudo sdparm -vvv --command=sense /dev/sg1
>>> about to open device name: /dev/sg1
open /dev/sg1 with flags=0x800
    inquiry cdb: 12 00 00 00 24 00
    /dev/sg1: Pliant    LB1606R           D317
    Request Sense cmd: 03 00 00 00 20 00
      duration=36 ms
Decode response as sense data:
Fixed format, current; Sense key: No Sense
Additional sense: No additional sense information

Output response in hex
 00     70 00 00 00 00 00 00 f4  00 00 00 00 00 00 00 00
 10     00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00

Has anyone tried to put these SSDs into low power modes, I see here that sometimes a command like scli can expose lots of power modes, maybe SSDs use different --pc= values to spinning rust?

Cheers
Richard

 

[Sinister Crayon]

I've got a couple of these in my ZFS. They're not really designed to be put to sleep or low power modes and frankly are pretty old. These were commonly used as OEM equipment in Dell storage arrays particularly Compellent SC4020 arrays as large read-intensive drives, usually in a hybrid environment where they were combined with spinning rust. As a result, I think power management was a secondary concern as (a) they were usually in mid-size environments where power was plentiful and (b) they were used as cache drives where their power budget was dwarfed by the other disks in the same array.

They're good drives though, but by modern standards they are VERY slow for writes (140MB/s). They're just raw MLC drives with no SLC "front-end" for write bursts and as I recall no caching of any kind... preferring to have writes committed immediately. This makes them reliable but sluggish. Also not totally sure about the lifespan of them but expect it to be much shorter if you have write-intensive workloads as these are designed for 90/10 read/write ratio.

 

[rthorntn]

Thanks, life wouldn't really be life without a few mistakes along the way, buying old MLC SAS drives was a mistake that I won't repeat. You live and you learn. Running eight LB1606R close together would go a long way to helping heat your house lol