Saturday, July 11, 2009

Lessons from the D945GSEJT Server

I was very happy to discover a comment on the setup of my Intel D945GSEJT home server today. I am glad to hear that my post helped you, Jules.

The home server works very well. I have learned a lot in the few days that the system has been running, and I felt it was time to share some of the knowledge I have gathered so far.

My choice of building the system in a fanless case with a built-in power supply was not the best. A power supply inevitably produces some heat, and with the whole setup being fanless, the harddrives reported temperatures close to 60 degrees Celcius. The specifications of the drives said that this was slightly above the upper safe temperature limit for operation. I changed to an external 12VDC adapter, and got the temperature of the harddrives down to about 40 degrees Celcius, which is perfectly acceptable.

The D945GSEJT board offers two power connectors, a 12VDC connector on the back panel, and a 4-pin 12V ATX internal connector. The Technical Product Specification of the board says that the 12VDC connector is "preferred", but does not in any way explain why that would be so, which is very strange. Connecting a mini-ITX power supply (with one 4-pin connector and one 20-pin connector) requires you to short two pins on the 20-pin connector, since this is the signal that the motherboard normally gives to the power supply to make it start and deliver the correct voltages on all pins. This is not anything I recommend in any way, but it was what I had to do to be able to use the built-in power supply of my mini-ITX case. I suspect that Intel had the idea that you would use some special power supply which is always on and only has the 4-pin connector, but I have not found any such supplies. My case gave me small electrical shocks using the internal power supply, which might have been caused by my unorthodox solution, but it might just have been the power supply that was dodgy. I am glad I switched to the external power supply, which has none of these worries.

Getting acquainted with mdadm for managing the RAID, and smartmontools for monitoring hard drive health was an essential first step in learning to administer my new home server. It turned out that one of my hard drives had a bad sector, and I got to apply this knowledge almost immediately. Emails from smartd started pouring in, telling me about the problem on the drive. The selftests that I had scheduled for the hard drives had fortunately located the error to a sector which was towards the end of the drive, which was probably not occupied by any data. The solution I ended up using was hdrecover, an extremely simple (293 lines of C code) program that tests the readability of each sector on a drive. If an unreadable sector is found, the program writes some data to it, forcing the drive to mark the sector as bad, an relocate it. In my case, being fairly certain that the defective sector was not occupied by any file, this was a solution as good as any. If you want to locate the file that occupies a certain sector, this can be a bit tricky. I found a howto on this subject, but I am not sure how I would get it to work in my case, with partitions on an encrypted LVM partition.


  1. Anonymous5:06 AM


    Can You comment a file transfer speed over lan in home network?

    M P from land called eart ;)

  2. I'm not sure exactly what you mean. I haven't experienced any problems with the LAN connection since I installed the correct driver for the board NIC. Doing a very unscientific test this morning, the transfer speed was about 7.5 MB/s (I have a 100Mb/s LAN, and there might be other bottlenecks). If you have a more specific question, please let me know.

    Best Regards,

  3. Anonymous3:25 AM

    Hey! I'm thinking of buying the same board for NAS duty, but i want to stick in 4 HDDs in a RAID-5 setup. Do you think the board's PSU can handle the extra load of four drives?


  4. The board itself does not have a PSU. Instead, you can connect either a 12VDC source on the back panel, or a 12V 4-pin ATX connector internally to the board (see my post). I currently use a 60W AC-DC adapter, which is enough even for maximum load (board ~20W, hard drives 2*10W, memory 5W). The hard drives are connected to the power connector on the board.

    For a 4 HDD setup, I guess you would need a SATA contoller card (~15W?, and perhaps a PCI riser card?), since you only have two SATA ports on the board. The two extra disk drives would consume about 10W each. I've seen AC-DC adapters up to 150W. If there is any risk of frying the board with such high wattage I don't know - I haven't seen anything about it in the product guide at least (a highly recommended read before you start building, link in the blog post).

    Another possibility is to use the 4-pin ATX power connector, and connect the hard drives to the power connectors of the mini-ITX PSU directly (read the note about this in the post though). In that case I can't see any problems with the setup.

    Best Regards,

  5. Anonymous8:59 AM

    75 MB/s - reading from or writing to "Home server" ?

    M P

    PS SRY - my native language is not an english ...

  6. That was 7.5 MB/s writing. Reading, it was a bit higher; 8.7 MB/s. Like I said, I don't know where the bottleneck is; if I would get higher speeds with a Gigabit switch or if the hard drives set the limit. Hope this helps.

    Best Regards,

  7. Anonymous9:36 AM

    sudo hdparm -tT /dev/sda"driveletterwhatisinyoursystem"

    75w/87r is good result in 100 Mb/s lan ;)

    M P

  8. Those hdparm tests were a nice tip, thanks! I got about 600 MB/s for cached reads and 100 MB/s for buffered reads. I also remembered that when I resynced the two drives of the RAID1, the transfer rate was 70 MB/s, which gives some indication about the write speed. So I guess then it's pretty clear that the 100 Mb/s switch is what limits the transfer rate to and from the server.

  9. Anonymous1:03 PM

    Next line in my ToDo list is - ordering this board ;)

    M P

  10. Anonymous9:10 PM

    Most interesting - I'm also thinking of this board for NAS duty - but will be needing at least 4 drives. Is a PCI riser is required in addition to the PCI SATA card?

    Looks like I'll need to do the ATX supply trick to get the wattage needed for 4 drives on spinup though.

  11. I guess you read the post about connecting multiple drives ( In light of that, I would definitely go for the ATX PSU solution when connecting four drives.

    Whether or not you need a PCI riser depends entirely on the case you are using. With my case, a PCI riser is needed, and the use of a PCI card prevents the use of two hard drives. My guess is that with a larger case, that can fit four drives and a decent power supply, chances are that you don't have to use a PCI riser.

    Thanks for reading, and good luck with the build!

  12. Anonymous6:08 AM

    Hi Jonas,

    I've also chosen Intel D945GSEJT for my WHS setup.

    Yesterday, me and a friend tried to assemble the rig, but we discovered that the board doesn't agree with the ATX PSU that I've bought. It's a shame, cause I've got an efficient Antec EarthWatts PSU (I went for the whole energy efficiency theme with this rig -- lo-power board, green disks etc.).

    Anyway... What I'm thinking now, after your post is: ditching the ATX PSU entirely, and going for an external 12V DC power supply. I have one 2,5" 160GB HDD for OS and one 3,5" WD Green 1TB HDD for data.

    External PSU should be enough to keep this combo running, and I should be able to add another WD Green HDD for storage if necessary.

    The power calculation is this...

    If I take regular-load operating power at normal read/write HDD load (nominal values), the calculation is this: approx 10W for the mobo, 2.5W for the 2.5" HDD, 5.5W for the 3.5" HDD. That adds up to 18W for 2 HDD setup and 23.5W for 3 HDD setup.

    But.... There's a dilemma....

    What made me think is this: WD Green spec sheet says it draws 1.671A peak current, and at 12V that's approx 4 times its operating power at normal R/W load.

    If I consider that, max load estimate is this: mobo draws 12.5W under max load (this is from the Intel's manual), 3.5" WD Green HDD draws max 20W (based on 12V and 1.671A peak current -- WD tech specs), 2.5" WD Scorpio Blue HDD draws max 12W (estimate, based on R/W load of 500mA at 5V multiplied by the factor of 4 -- assuming peak values on WD Scorpio relate to R/W power values the same was as they do with the WD Green).

    This means that I'm looking at peak load of 44W for 1 x 2.5" + 1 x 3.5" combo. If I add another 3.5" HDD this goes to 64W peak power.

    Now, I'm aware that the peak load can probably occur only during startup, and that it can last up to a second or so...

    What do you think? How does your system behave so far?


  13. Srdjan,

    Thanks for your comment. As you read in my post, I had also thought of using an internal PSU for my setup, but even if I tweaked the PSU to function with the board, the external 12V adapter was a better solution in all respects.

    As for your question regarding multiple drives, I suppose you've already read my post regarding this issue ( I have had no problems with my setup, with two WD Green drives, so I guess your idea of having one 2.5" WD Blue drive and one 3.5" WD Green drive should work. With an additional 3.5", maybe it can work, since the power consumption at normal use is far less than the peak power consumption stated in the specification, but I don't know for sure. Please let me know how it works out if you decide to try it.

  14. I recently purchased this board and was curious about your solution of shorting the pins on the 20pin connector, as I was considering doing the same thing.

    How well did it work? What did you use to short the pins? When you say you received electrical shocks, did you have the jumper accomplishing the short in contact with the chassis or what?

    Good info so far, thanks.

  15. @Jason Thanks for reading my blog! For the record, I would not recommend shorting the pins, but if you go ahead and do it, it would be interesting to hear about your experiences. Shorting the pins was a brief experiment, which I aborted when I discovered that I was getting shocks from the case. I used a paper clip to short the pins, and I made sure the pin was not in contact with any part of the case or other components. I am not good enough with circuits to figure out why the shocks occurred, but I got them when the computer was turned off (but the shorted power supply was still on, which it should not be in a properly wired computer, where the motherboard controls the on/off state of the power supply). All in all, having an external power supply seems like a much wiser solution. Let me know how things are working out for you!

  16. I'd love to go with an external AC adapter, but I'm concerned that the 60W I'd be limited to would be enough to power the two 3.5" 5400rpm HDDs that I need in there, as well as a CF adapter which should be negligible.

    I see you're running a 2.5" and a 3.5", but that's a pretty big difference in spin-up power. I've yet to read a single forum post anywhere with someone confidently stating that they're running two 3.5" HDDs in this configuration with an external power brick.

  17. @Jason I have been running two 3.5" HDDs from the start (albeit WD 1TB Green, which are low on power consumption) with no problems whatsoever. The system has been constantly up for the last year. The current uptime is 30 days, and that is only because we moved a month ago :).

  18. Oh awesome. 60W external brick it is then. What's the model number if you don't mind? I'm running two Samsung EcoGreens so hopefully they're comparable.

    Thanks again for the info.

  19. @Jason My AC adapter is manufactured by Travla, and has model number SSA-0601S-1. I looked up the company on the web, and I think this page shows the AC adapter that I have: . Good luck, and let me know how things are working out for you!

  20. I finally got everything in the mail and put together and figured I'd give an update. The 60W brick so far has been more than enough to power the board, CF card and two 5400rpm 3.5" HDDs, just as you said. Everything is working very well, staying cool and performaing far better than I had expected from such a low-power machine.

    Thanks again for the input.

  21. @Jason You're welcome! Great to hear that you've got the computer set up and running well. My system is one of my best buys ever, acting as a Samba, SSH and web server, with now over a year of hassle-free uptime, and I'm sure you'll be just as pleased with your setup.

  22. Anonymous2:13 AM

    Hello, I know its an outdated topic but i found no other related blog to turn to for help.

    Well i assembled my system with the
    *Intel D945GSEJT
    *WD 320GB 3.5" HDD
    *12v 8CM internal case fan &
    *An 12v 5amp external power brick for the power supply.

    Well im gona use this system like 24/7 non-stop for an extended period as an independant download server. Will i be having any problems with regards to heat or other problems because of prolonged use. Is the system stable??

  23. Well, my system (D945GSEJT and two 1TB WD Green HDs) has been running 24/7 since I built it two years ago. The current uptime is one year, since that was when we moved to a new apartment. I think you will have no problems with your setup.