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Le 15/02/2015 16:48, hp cre a écrit :
I have, at home :) I have 3 Banana pi (each is an OSD), and 1 Odroid C1 (which is acting as MON, and in the same time, hosts other LXC servers) Each banana pi has a Sata 240 GB SSD + 1 USB 1,5 TB drive. In a few words : It works. But it has lots of limitations, and it's absolutely not advisable to put production on it. I you want to experiment on this, some advices : -> You need recent kernel on Banana pi & Odroid to have good Ethernet bandwidth (over 600 Mbit/s) -> Another reason to put a recent vanilla kernel (3.6.18 or more on Bananapi) is stability, I had lots of glitches with 3.10 customs Bananapi kernels ( with data corruption :) ) -> If you plan to use XFS, BEWARE !!! there is miscompilation with XFS on arm if you use standard (-O2) optimization. Use (-Os) to have a reliable XFS module. -> banana pi has Sata, performance is OK for read (over 150 MB/s) but it's definitively SLOW for writes (not more than 40 MB/s), so putting an SSD on Sata for journal don't have much interest. In fact you have better bandwidth using 2 separate USB 2.0 disks !!! (Bananapi has 2 independents USB channels) -> Bananapi (and Odroid) are limited to 1 GB of RAM, it's adequate for OSD in the 1/2 TB range, not more, or you'll end up swapping like mad (on slow device) -> Bananapi or Odroid are not servers anyway so you don't have any kind of error protection !!! And even if you avoid all those traps, you'll find that performance is not that great. Using RBD, I can barely reach 20 MB/s (which is not THAT bad). Even with ONLY SSD pool (the root cause is : you need journal anyway and limitation is Bananapi (in fact Allwinner A20) Sata chip or driver . Odroid C1 has an eMMC channel, but it seems you won't have better throughput using this.... I can give further details if you wish, Cheers
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