[DRBD-user] Syncer rate limit of 700000K/s...

Diego Julian Remolina diego.remolina at ibb.gatech.edu
Mon Oct 2 14:09:19 CEST 2006

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


> basically, yes.
> but I seriouly would envy you for having an io backend that can deliver
> a write performance of more than 700 Mega octets per second :)
> 

This is now very possible using the PCIe Areca Raid Controllers with the Intel 80341 chipset and 14 
SATA drives (Look at the benchmark results):

http://www.areca.us/
http://tinyurl.com/qrt7m (Translated article)
http://tweakers.net/reviews/639 (original article in German)

I currently have the old PCI-X versions of the 4, 16 and 24 Port controllers which are slower. At 
the time when the machines were put together the sweet spot for hard drives was in the old SATA 150 
disks since the SATA II drives had just been released and were too expensive. I only get up to 
231,276 Kb/s writes and 157,140 Kb/s reads on Raid10 with the old Areca controllers, as shown in my 
benchmarks page:

https://services.ibb.gatech.edu/wiki/index.php/Benchmarks:Storage#Benchmark_Results_3

However, my drbd configuration is limited by the single gigabit link and with drbd I get 123,738 
Kb/s (basically filling up my Gigabit card bandwith) writes while reads remain at 156,715 Kb/s. I 
know I could channel bond, but I chose not to, I am happy with the current speeds and do not need more.

While the areca drivers are still not included in the mainline kernel, it is rather easy to compile 
them and have your machine using those controllers for storage. However, I have not tested a 1280 
PCIe card yet.

I can only assume that with the new PCIe cards and 10Gbit network controllers you could achieve 
700MB/s. However, the 10Gbit network controllers seem to be highly expensive at the moment, so 
unless you can justify spending ~$4,000 in a network card, it is not worth it.  I have not updated 
my 10TB server recipee lately to use the new SATA controllers, but you can (at least in the US) 
build a 10TB server for just under $10,000 with regular gigabit cards. See:

https://services.ibb.gatech.edu/wiki/index.php/Howto:Hardware:Assembly#3U_File_Server_Under_10K

I assume you could add 2 Quad Gigabit PCI-X cards for about $450 each and channel bond them for drbd 
and that will in fact give over the 700MB/s you want, but I have never tried that and I dod not know 
if you can channel bond 8 controllers.

Diego



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