case dilemma

[Andrew Barnes]

Hi, I'm new to the forum but have been lurking on IRC for the last week.

I'm looking to build a FreeNAS server. Currently, I'm stuck on the case.

Requirements are:
* at least 4 3.5 inch bays for current array
* at least 3 3.5 inch bay for backup
* hot swap would be nice.
* micro / uATX support
* an efficient power supply at 30-80 watts (peak power is expected to be 120 watts) - hard to find!

I thought I had nailed this with a recent spend on a 2nd hand SC745TQ-R800 SuperChassis (£65). It has 8 3.5 inch bays. although it is large, the worst bit by far is the power supplies. They are so in-efficient at the watt range I require, that they pull OVER twice the amount of power required!

FSP 500 watt Bronze 80+ 1U = 40watts
R800 (both of them) = 100watts
800 (one of them) = ~70watts

running exactly the same equipment.

My options so far are:
1) I sell the case and start again (although, I can not find many other cases that have front loading drives)
2) I buy the platinum or gold rated PSU's for this case - however, they are rated even higher wattage (920w) - and so I imagine that efficiency curve will still be lacking under 10% loads (where I expect my server to be most of the time) even if they are "efficient" at 80% load.
3) I customise the case to fit another PSU, I do have some bronze 80+ PSU's, but they are 1U and will not fit (at all) in the PSU slots of this case. But would fit underneath the PSU cage, if I fabricated some method of supporting the PSU.
4) what else can I do?

I didn't expect to have such a headache over the case and PSU. I've learn't a lot about PSU's recently, having first thought the R800's must be broken...nope, they are just not designed for efficiency at such low loads :(

Please give me some encouragement...

 

[marbus90]

There's still the PWS-501P-1R which runs at 88% efficiency under just 50W of load, equaling a wall measure of 57W. Other idea is to search for a 743 series chassis, those run standard ATX PSUs.

Front-loading or Hot-Swap in general might be overrated. Also, did we talk about the risk of backing up in the same chassis? Probably more interesting to get HP Microserver (has hotswap)/Dell T20/Lenovo TS140 x2 and fire up the second server as needed - and also having a spare server in case the main one goes derp.

 

[DKarnov]

I'd just hack the case to fit a regular ATX. Difficulty really only depends on how clean you want the hack to look. Keep in mind that case's 5000! RPM fans are going to be both power hungry and very loud, probably even if PWM'ed down.

When worrying about efficiency, keep in mind how many KW per year you're actually talking about saving, and the cost you pay for same. It's a good idea to go for high efficiency from the start, but if you've already got the equipment it may be hard to argue buying new hardware with just a few percent gain will pay for itself in any reasonable timeframe.

marbus90 has a point about doing backup in the same case, and 3-4 disk pools are pretty space-inefficient. You could just take those same disks and do a 6-7 disk RAIDZ2 or Z3.

 

[Andrew Barnes]

PWS-501P-1R, I forgot this suggestion - I think at the time I didn't think it would fit as its not listed part for this case. However, the sizings all match up. the only unknown is if the DPU/PDU PSU backplane design is consistent across these PSU's? This is definitely the best option if money was no object - maybe I bite the bullet.

Modifying the case I think I could do reasonably well. I wonder if I could find the cage for the atx 743 model. I suspect they just swap out, with just cutting out the back a little.

The TS430 has my attention, if I could get one cheap and swap the 1225 for 1230v3.

Regarding the backups being in the same chassis - I don't have the option of remote backup exactly, currently I use a DAS and an DIY relay controlled PSU. its turned on for backups, and powered off again after.
I'd like to backup for
*) protection against the users/me (deleting important stuff)
*) protection against the volume/pool going down
*) fire / burglary

unless I'm missing something, in chassis or out of chassis (but still in the same site) doesn't make much difference to fire or thieves (unless its hidden in the walls or something! - not a bad idea). these disks are odd disks, I don't think they would bring reliability to the main array.

I really want the backups for the first 2 options, and then do something more basic remotely with some 'friend-share'

 

[marbus90]

You could start out with a single PWS-501P-1R and add another one later, when money allows. You just can't mix a 800W and a 500W PSU in the same chassis. Also the 500W one should be considerably lower on the noise aspect than the 800W one. Feel free to contact Supermicro's support, they should be able to help you out there.

Also there is almost no reason to switch from 1225 to 1230.

Re backups I'd say that expanding to a raidz3 on 7 disks against hardware errors plus ZFS snapshots against user error should be a reliable option. In addition to that have a copy of the most important files on every client.