SlimNAS on Koolu Thin Client

Summary

The Koolu Thin Client is a compact small system, and its strengths have been discussed in this thread. The hardware is a relabeled FIC Ion A603 Mini PC.

Have had mine a week or so, and spent some time with it. For libraries that can fit on a 2.5in PATA disk the Koolu is a compact SqueezeCenter platform with usable performance. It's much slower than a desktop PC, but still usable. From the SB3 interface, it is mostly indistinguishable from a desktop PC (scrolling through each track is not fast on either, most everything else is).

Installing SqueezeCenter on Koolu

For CDN $199 + PATA disk, the Koolu Thin Client is an attractive solution. It is efficient enough to run 24x7 without much guilt. Its network performance is poor, but definitely sufficient for a few SB3s (I have 3, the Koolu could support more). Navigation of the Squeezecenter interface is not very fast, but still usable.

Installing SlimNAS on it is as trivial as:

1. Install hard disk in Koolu (covered in printed manual that accompanies device)
   • Internal drive bracket, short 44-pin IDE cable, and all mounting hardware are included in the box
   • A Philips head screwdriver is required to install the disk.
   • The RAM module and NIC are on the bottom of the board, be careful not to damage them extracting the board from the case
2. Burn FreeNAS CD image
   • Be sure to use 0.687b1 or later (based on FreeBSD-6.3). Earlier versions (based on FreeBSD-6.1) will not boot on the LX800
3. Boot Koolu from USB CDROM drive
4. Select installation method of your choice from console menu (item 7), wait for copy to complete
   • I installed FreeNAS on the first partition and used the rest of the disk for storage (item 2)
5. Install SlimNAS
6. Enable whatever method you prefer to transfer music through the FreeNAS web interface (e.g. FTP, CIFS/SMB, rsync, NFS) and upload
7. Configure SqueezeCenter

There aren't any substantial surprises getting this set up. Some familiarity with UNIX would be good (e.g. mounted disks are under /mnt, etc.), but is probably not a requirement.

Performance

SqueezeCenter is a well known resource hog, so performance for any small/embedded system s a concern. Performance is usable, but not impressive with a PATA internal drive.

• Both systems have 1GB of RAM installed. D201GLY2 is DDR2, Koolu is DDR
• Procedure: Click on each "activity" item from Home screen. Timing done using Faster Fox extension for Mozilla Firefox
• Results are best of 3, done in cycle (Albums, then Artists, etc.)
• Items to display as 50 (default)
• 7.0 uses its default skin, not "classic", has library statistics disabled
• Library used is a 55GB subset: reported as 8,407 tracks, 686 albums, 254 artists
• Koolu appears CPU bound during navigation of web interface. D201GLY2 might as well, but it's hard to notice using top

Did not test USB drives attached to Koolu as performance was (IMO) not usable. The D201GLY2 times are themselves not very impressive for a local web application on dedicated hardware (the FreeNAS PHP interface rarely takes more then 0.300s to display).

The overall cost of these two systems is not very different (probably less than USD $100), though the D201GLY2 has a 40x40x10mm fan.

Outstanding Issues

The largest issues for SqueezeCenter on the Koolu are (in retrospect) foreseeable:

External USB Storage

USB is the only choice for external storage, and performance for the USB enclosures I have tried (thank you Microcenter) has been awful. Most are based on Sunplus or JMicro USB2-SATA bridge chips that perform 5-7x worse than SATA/IDE per command. Throughput is not too bad for the USB-SATA enclosures (often >20MB/s), but this does not help responsiveness for SqueezeCenter.

Results for a 750GB Western Digital SATA2 disk connected using a Vantec NexStar 3 USB2 enclosure:

koolu:/# diskinfo -c da1
da1
        512             # sectorsize
        750156374016    # mediasize in bytes (699G)
        1465149168      # mediasize in sectors
        91201           # Cylinders according to firmware.
        255             # Heads according to firmware.
        63              # Sectors according to firmware.

I/O command overhead:
        time to read 10MB block      1.446477 sec       =    0.071 msec/sector
        time to read 20480 sectors  15.362916 sec       =    0.750 msec/sector
        calculated command overhead                     =    0.680 msec/sector

A 400GB Western Digital PATA disk of 2007 vintage:

koolu:~# diskinfo -c ad0
ad0
        512             # sectorsize
        400088457216    # mediasize in bytes (373G)
        781422768       # mediasize in sectors
        775221          # Cylinders according to firmware.
        16              # Heads according to firmware.
        63              # Sectors according to firmware.

I/O command overhead:
        time to read 10MB block      0.198051 sec       =    0.010 msec/sector
        time to read 20480 sectors   2.890807 sec       =    0.141 msec/sector
        calculated command overhead                     =    0.131 msec/sector

As SqueezeCenter does considerable IO (checking dates, reading chunks for files, MySQL, etc.) this has an unfortunate impact on Web UI performance.

• Same enclosures exhibit poor IO performance from Windows on other PCs
• SqueezeCenter performance under Linux (CentOS 5) is equally poor compared with FreeNAS
• Under SlimNAS, library rescans require 47 min using USB enclosure, 32 min using an old 5400RPM 2.5in disk connected using PATA

Am satisfied that fault lies with the USB bridge or subsystems. The Koolue has no PCI (or mini-PCI) slots for adapters and no SATA to adapt to eSATA.

• Any better USB2-SATA enclosures on the market with FreeBSD support?
• Does the LX800 have incredibly poor USB2 support?

Realtek 8139 NIC is CPU-limited

Using rsync to copy files, it wastes just under half of the available CPU time on interrupts (in FreeBSD/FreeNAS/SlimNAS). This reduces effective throughput to under 40Mb/s (5MB/s) despite the 100Mb/s interface. Not a problem for daily SlimServer use, but it makes transfers tedious, e.g.

last pid:  1286;  load averages:  2.07,  1.53,  0.80
22 processes:  2 running, 20 sleeping
CPU states: 24.9% user,  0.0% nice, 30.7% system, 44.4% interrupt,  0.0% idle
Mem: 16M Active, 306M Inact, 66M Wired, 17M Cache, 51M Buf, 868K Free
Swap:

  PID USERNAME  THR PRI NICE   SIZE    RES STATE    TIME   WCPU COMMAND
 1224 root        1 128    0  2744K  1960K RUN      3:09 43.51% rsync
 1223 root        1   4    0  2456K  1668K select   0:52  7.91% rsync

In a system with more processing capacity than the 500MHz LX800 this would be less of an issue.

Operating Temperature

Many laptops are worse, but the Koolu will become warm (35-38C) after extended periods of full load. This happens more often than it should-- surely the inefficient NIC contributes to this. Not sure whether another LX800 based platform would operate at a substantially lower temperature (e.g. PC Engines ALIX, Soekris net5501, Fit-PC, etc.), but it would be nice.

It's not a major problem, but the temperature puts most 2.5in disks at the top end of their operating temperature, which is not good for longevity.

• Disk reports 39C when not spinning, rises to 53C after a few hours streaming

Conclusion

Lots of compromise is required to love the Koolu as a SqueezeCenter host. It's not cost efficient compared to a cheap PC (like the D201GLY2) and offers marginal performance. It is usable, but not much more.

Think I'll use it as a SIP router instead.

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