H3+case 3 -> 2.5" NAS?

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fvolk
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H3+case 3 -> 2.5" NAS?

Post by fvolk »

How does the H3 work as a low-power and silent NAS with 2.5" drives, so with the case type 3 design?
Let's try this.

Theory:
Power consumption depends on SATA link power and power used by disk itself.

SATA link can be set "min_power", "medium_power", or "max_performance".
More performance -> everything active; less power-> link goes to sleep and requires time/latency to wake up again
set SATA power level like:
for i in /sys/class/scsi_host/host[01]/link_power_management_policy; do echo min_power > $i; done

2.5" disk power can be managed with a disk's APM setting:
hdparm -B xxx /dev/sdX
-B 255 = maximum performance, disk spinning and heads always flying
-B 128 = disks spinning, heads park after a few seconds of idle. This is the mode 2.5" consumer disks for laptops are usually shipping by default, parking the heads saves a bit of power and makes a mechanical disk more robust to shocks, at a cost of a slight latency on access.
Note that the APM levels may be manufacturer specific.

One can also ask the disks to spin-down immediately manually:
hdparm -y /dev/sdX.
Upon next access they automatically spin-up again.

One can set an auto spin-down timer on a disk, so if a disk does no I/O operations for some time it spins down.
E.g. hdparm -S 241 /dev/sdX sets the timer to 30min
(read hdparm manpage for values of -S option)
This is useful to auto spin-down the disks over night, upon next access in the morning the disk comes up again.
Note that frequent spin up/down is said to wear out a disk mechanically.
Note also that some background processes can prevent the disks from (long) sleeping - e.g. a SMART status daemon that periodically accesses the disk.


Practice:
one H3+, with 32GB(2x16), a NVMe Samsung 960 SSD,
2x HGST 500GB with 5400 rpm,
as a headless server, 1GBit network attached.

base power observed without disks attached: 1.6W (see other thread viewtopic.php?f=173&t=45620)
with disks:

SATA link min_power:
1.9W disks spun down
2.9W -B 128
4.5W -B 255

SATA link medium_power:
4.2W disks spun down
5.4W -B 128
6.8W -B 255

SATA link max_performance:
4.7W disks spun down
5.4W -B 128
6.9W -B 255

...unscientifically measured at wall socket with a random cheap Wattmeter from Amazon

The numbers for 2x 2TB disks would be higher, as 500GB is single platter and 2TB are 2 platters.
5TB disks would be even higher.

Thoughts:
~2W for a x86 NAS on idle standby is awesome, ~4.5W for active idle also.
The H3 series is a serious choice for a small NAS if one is happy with the space offered by 2.5" disks.
I run a H2-based NAS with 2x2TB in min_power and -B255 mode since about 3 years and it works just fine: viewtopic.php?p=336777#p336777
I think overall the H3 will use a bit less power than the H2-based one, and the H3 offers more compute (TBD).
...so a switch to the H3 will likely happen in the near future.

Pic or it didn't happen:
h3nas.jpg
h3nas.jpg (52.5 KiB) Viewed 241 times
Thank you for the generous donation of the H3+ that made this evaluation possible... :-)
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odroid (Fri Nov 11, 2022 1:23 pm)

fvolk
Posts: 740
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Re: H3+case 3 -> 2.5" NAS?

Post by fvolk »

FAQ:
With this test setup, so far I have not observed a problem with initial power connection as I had with the H2-based one: viewtopic.php?p=265850#p265850

H3+ instead of H2. Different PSU. And I think I used the same disks, but I'm not 100% sure.
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odroid (Sat Nov 12, 2022 8:08 am)

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