Thx.... James Peach sent something similar to me too...... darn vfs objects :) Thx james :) I remember now on irix we had to do some stuff with these.....
I do not see the "cacheprime" vfs object on FC13 but I do see "readahead" so I guess I will start with that....... I also heard that there are some other I/O tuning that I can do in the Linux/FC kernel to maybe increase the read/write sizes....... The kicker here is that I am using an Areca 1880-ix-16 as well as an ATTO R680 card in my boxes and they do not work very well with small I/Os..... They are both 6Gbit technology and I have 16 X 2TB fast Hitachi drives in the connected raid....... No one has issues with reading/writing one file....it is where one wants to read or write say 20-40 files simultaneously it all goes to heck with small I/Os to/from the raid cards on Linux. I use "fio" as a test vehicle. It runs over 10Gbit port from a client to a 10Gbe port on my FC13 system.....using samba or netatalk....simulating 20-40 video users.... to see home many read/pread's I can get under 38ms/1MByte...... It is a requirement we have for Video editing......I have tuned Mac OS using the ATTO R680 card and it has no problems with low latency for 20-30 sessions/users......The most I can get out of FC13 is maybe 8-10. So it looks like I have homework to do to get Linux/FC13 so it handles I/O's bigger :) Thx chris On 1/18/11 12:34 AM, Volker Lendecke wrote: > On Mon, Jan 17, 2011 at 10:14:04AM -0600, Chris Duffy wrote: >> We are testing Samba 3 (and 4) on Fedora Core 13, >> 10Gbit connection with a Mac OS 10.6.4 system >> as the client. We will be adding some Windows >> machines sooner or later with 10Gbit interfaces. >> >> We are seeing 100-150MBytes/sec read or write >> performance between the Mac and the FC13 system >> over 10Gbit interface but it should be capable of >> 400-500MBytes/sec. We have a local raid >> on the FC13 system that runs 1GByte/sec locally >> using an Areca 1880-ix-16 raid card (6Gbit version). >> It has 16 fast Hitachi disks in a Raid5 format >> using xfs filesystem. >> >> The problem here is that samba is poking the Areca >> at 128KByte I/O's on preads and writes, i.e. >> shown to us using strace on the smbd daemons >> that are running. Using vmstat/iostat/sar utilities, >> we see 100% utilization of the Areca card because the >> average wait time is real high and the average >> queue length to it is also high......too many >> small I/O's..... >> This is not the case if I run "fio" or "dd" locally >> to/from the Areca's raid using 1-4MByte I/O's. >> I see fast I/O... >> >> I do not see any way to increase the size of Samba's >> pread/write's in the smb.conf documentation. I >> am sure it may be just a matter of getting the source >> code and making some changes to allow larger >> sized IO's but........and of course I suppose Windows >> clients may complain but.... >> >> I remember that back in the old Irix days with the >> group of engineers in Australia I worked with, >> we had Samba screaming fast but not sure if they >> tweaked the version of Samba on Irix to do this. >> >> Can you guys come up with a way for us to allow >> the reads/writes to/from the disks to be tunable >> up to say 4MB in size? > You might want to play with "write cache size". This will > only tune writes though. And it will only work for oplocked > files. I'm not 100% sure that OS/X plays nicely wrt oplocks. > > For reads, we need to take a much closer look at your real > workload and see if we need to use some kind of preopen, > prefetch or so module. We need to closely work with the > kernel buffer cache and potential readahead kernel > algorithms. > > With best regards, > > Volker Lendecke > -- Chris Duffy Technical Support Small Tree www.small-tree.com <http://www.small-tree.com> Direct 651-209-6509 X305 Mobil 651-303-9613 Yahoo:chris_duffy6288 AIM:chris.j.du...@comcast.net -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/options/samba
