In my continuous quest to endless disk storage, I have ordered two D-Link DNS-323 NAS devices. Since this is my second NAS device (first was DSM-G600 which is PowerPC) I have some experience, so let's see what is inside this (big, black, heavy, metal) box.
dlink-DFDADE:~# uname -a Linux dlink-DFDADE 220.127.116.11-arm1 #30 Mon Aug 18 14:19:14 CST 2008 armv5tejl GNU/Linux dlink-DFDADE:~# free total used free shared buffers cached Mem: 61904 54808 7096 0 11824 30592 -/+ buffers/cache: 12392 49512 Swap: 1060208 0 1060208 dlink-DFDADE:~# cat /proc/cpuinfo Processor : ARM926EJ-Sid(wb) rev 0 (v5l) BogoMIPS : 331.77 Features : swp half thumb fastmult edsp java CPU implementer : 0x41 CPU architecture: 5TEJ CPU variant : 0x0 CPU part : 0x926 CPU revision : 0 Cache type : write-back Cache clean : cp15 c7 ops Cache lockdown : format C Cache format : Harvard I size : 32768 I assoc : 1 I line length : 32 I sets : 1024 D size : 32768 D assoc : 1 D line length : 32 D sets : 1024 Hardware : MV-88fxx81 Revision : 0000 Serial : 0000000000000000So, it's a 330 Mhz ARM with 64Mb or RAM (expandable to 128Mb with SMT soldering, sic!) and a disk. D-Link provided firmware has oldish 18.104.22.168 kernel and usb modules just for printer support. Even worse (than usb keychains or wifi dongles not working) is RAID performance: in RAID0 (which is called performance by firmware) I get 32 Mb/s from single disk and just 37 Mb/s from stripe.
But, all is not bad, because we can install full Debian on DNS-323 which brings us latest software which is just apt-get away, LVM, and support for various recent hardware.
After flashing, and updating to latest Debian arm kernel for orion platform I got 44 Mb/s from single disk and 42 Mb/s from RAID0. So I'm really hitting some bus bandwidth problem somewhere... Even worse, RAID1 is just 36 Mb/s, suggesting that 330 Mhz arm just can't keep up with pair or 1.5Tb SATA drives connected to it.
Next logical step would be to think about a way to use drives individually, because aggregating them on device doesn't make sense. With 220 Mb/s bandwidth on network (which is supposedly 1 Gb/s, sic!) it should be possible to get 44 Mb/s of disk speed onto another machine. I tried vblade which provides AoE server in user-space and it's slow: just 8 Mb/s to directly connected ThinkPad over cross cable.
I will test NFS (and CIFS if everything else fails), but I can guess that I will end up using this device for incremental backup dumps on top of ext4 or maybe nilfs. We'll see...
Update: I didn't choose DSM-323 randomly. When I was deciding which NAS device to buy, I watched Debian on Network Storage Devices and Other Devices which is embedded below for your viewing pleasure (download hi-res version). Orion related stuff starts at about 13:50.