Dan, Does something like this help for SAMBA? http://www.e-rave.nl/disable-creation-of-ds_store-files-on-samba-shares Negative lookups are a particularly expensive operation on distributed filesystems, GlusterFS in particular. It has to check through each brick to see that the file *really* doesn't exist, increasing the lookup overhead immensely. If samba doesn't pass these queries to GlusterFS, it might help a lot. -- Adam Tygart Beocat Sysadmin On Wed, Dec 19, 2012 at 8:29 PM, Daniel Mons <daemons at kanuka.com.au> wrote: > I'm rolling out 4 lots of 6-node GlusterFS setups for my employer. Each > node is ~33TB of RAID6 backed storage (16x 3TB SATA disks in RAID6 with a > hot spare hanging off an LSI controller, with 2x SSDs configured for > caching), and Gluster is configured in distribute-replicate. Each cluster > is 200TB of raw space, 100TB usable after replication. When complete, there > will be 4 of these clusters. > > Nodes are configured as XFS with 512byte inodes, running a fully patched > CentOS6 and Gluster 3.3.1. Each node has a 6 core Xeon processor (with HT > for 12 threads) with 32GB of RAM. Each node runs 2x 10Gbps Ethernet over > fiber in a bonded configuration (single IP address per node) for a full > 20Gbits per node. > > GlusterFS FUSE performance under Linux is great (clients run a mix of Ubuntu > 12.04 LTS for workstations and CentOS6 for servers). Samba performance back > to Windows 7 clients is great. NFS performance via both Gluster's userspace > setup as well as CentOS6's native NFS4 kernel server are great to most other > systems where we can't get the Gluster FUSE client loaded (large > industry-specific Linux boxes that are provided by vendors as a "black box" > solution, and only allow limited access via NFS or SMB/CIFS). All testing > so far under those conditions proves orders of magnitude faster throughput > than our existing single NAS solutions. > > MacOSX Finder performance is a problem, however. There's a huge bug in > MacOSX itself that prevents using NFS at all (discussions on other mailing > lists suggest it occurred somewhere around 10.6, and continues through into > 10.7 and 10.8). > > Mounting via SMB under OSX is more stable than NFS, however in folders with > a large amount of files, Finder goes looking for a corresponding Apple > Resource Fork file (for every "filename.ext", it looks for a > "._filename.ext"). Running tcpdump and wireshark on the Gluster nodes shows > that the resulting "FILE_NOT_FOUND" error back to the client takes a very > long time. Configuring a single node as a pure NAS with the same software > (but no Gluster implementation) is lightening fast. As soon as GlusterFS > comes in to play, reporting of each "FILE_NOT_FOUND" slows down the process > dramatically, causing a directory with ~1000 images in it to take well over > 5 minutes to display the contents in MacOSX finder. > > This problem is resolved somewhat by switching to AFP (via Netatalk loaded > on the GlusterFS nodes), but it has it's own problems unique to that > protocol, and I'd rather stick to GlusterFS-FUSE, NFS or SMB in that order > of preference. > > It's worth noting that through the terminal, these problems don't exist. > Mounting via SMB, browsing to the volume in terminal and running "ls" or > "find" style commands retrieve file listings at a similar speed to Linux and > Windows. The problem is limited to clients using Finder to browse > directories, and again particularly ones with a large number of files that > don't have matching Apple Resource Fork files. (Of note, creating empty > files of the matching "._filename.ext" format solves the performance > problem, but litters our filestores with millions of empty files, which we > don't want). > > I understand the problem is not strictly Gluster's issue. Finder is looking > for a heck of a lot of files that don't exist (which is a pretty silly > design), and it tends to occur only with Samba re-exporting GlusterFS > volumes that we can see. And likewise Apple's NFS bug that has now been in > existence across three releases of their OS is pretty horrible. But > hopefully I can at least describe the problem and prompt some testing by > others. > > I haven't had a chance to test a MacOSX FUSE client due to time constraints, > but that would at least answer the question if the problem is Gluster's lag > in reporting of files not found, or Samba's. > > -Dan > > > _______________________________________________ > Gluster-users mailing list > Gluster-users at gluster.org > http://supercolony.gluster.org/mailman/listinfo/gluster-users
