Apple Support Communities > Servers and Enterprise Software > Mac OS X Server v10.6 Snow Leopard > Discussions
2290 Views 11 Replies Latest reply: Mar 16, 2011 2:32 PM by Jeff Peach
Currently Being ModeratedMar 14, 2011 2:59 PM (in response to Jeff Peach)You're going to need to run some speeds and feeds, and figure out what the slowest piece of the connection is here, remove it or upgrade it or otherwise deal with the bottleneck, and iterate until performance is acceptable.
Likely candidates include overloaded or misconfigured WiFi networks, bandwidth in the WiFi backhaul, bandwidth into the server, I/O and disk bandwidth in the server, and possibly a few other pieces.
The most obvious culprits are an overloaded network connection somewhere. (That's because a GbE should be slower than the disks on your server.) Though available physical memory or other activity could well be constraining performance, as could WiFi devices interfering with each other, or MiFi or other rogue devices that are hammering your WiFi.
(I'm obviously assuming WiFi here and not wired GbE, but there are ways that wired GbE performance can tank, too. Bad or flaky switches, bad wires, mismatched speed settings, etc.)
The synch will shove the contents to the other end, with what doesn't exist. So you can end up synching from nearly nothing on up to most everything, depending on the state of the clients and the server.
As for synchronization overhead, I'd preemptively move all the stuff you don't need and won't change (eg: all of the stuff from last year) to another path in the local directory, or elsewhere, and keep all of that out of the default sync selection.
Currently Being ModeratedMar 14, 2011 3:16 PM (in response to MrHoffman)We have wifi but only a few teachers laptops use it, most of our connections are Gig nics -Cat6 cabling - gig switches. So, our connection to the server is very fast, copy a 500 mg file in under 10 seconds, but when 2 classes of students, especially 8th graders, log on, it slows.Intel Imac, Mac OS X (10.6.6), Lab- Intel iMacs
Currently Being ModeratedMar 14, 2011 3:47 PM (in response to Jeff Peach)I guess my immediate question is what exactly happens when a student logs on. Does the contents of their home folder have to travel across the network?Intel Imac, Mac OS X (10.6.6), Lab- Intel iMacs
Currently Being ModeratedMar 15, 2011 6:28 AM (in response to Jeff Peach)if these are all network homes and you're not redirecting folders, like ~/Library/Cache and others, you'll experience the delays you mention. i think you posted about this before, correct?
please check the client management whitepaper for tips: http://images.apple.com/education/docs/Apple-ClientManagementWhitePaper.pdf
when using network homes, the students' data isn't all copied over to local disk, so that shouldn't be your issue here. the homedirs can be huge, but the clients aren't reading or writing to all of the data on login. they're just mounting the homedir as a share.
when done correctly, redirecting the cache folder and others can work just fine.mbp 2.4, mbp 2.16, powerbook G4 1ghz, G4 400 mhz, dell test box, etc., Mac OS X (10.6.6), plain text 4 life
Currently Being ModeratedMar 15, 2011 7:42 AM (in response to foilpan)Yes, I have posted before about this and we thought we had solved the problem but after yesterday it returned. We nested home folders and totally rebuilt the servers. We have cleared the cache files of each 8th grader and that helped some. We have tried numerous times to redirect the cache folder to the clients, but every time we try it messes up another piece of software. For example, we redirected the cache folders and then we couldn't save HyperStudio stacks, which is our main multimedia software and I don't know why they couldn't save.
On another note, in the first period 8th graders where we have the most issues there are about 7 or 8 yearbook students that have massive iPhoto libraries, some in excess of 3 gb, could that be causing a slowdown? Thanks, I will take a look at the pdf file.
Do you have instructions on redirecting cache folders? Everytime I try it we run into problems.Intel Imac, Mac OS X (10.6.6), Lab- Intel iMacs
Currently Being ModeratedMar 15, 2011 9:44 AM (in response to Jeff Peach)We find any more than around 40 users with home directories logged in at once and it becomes slow, the CPU performance or RAM of the server doesn't seem to make much difference.
We found performance much better with many cheap XServers than a few well-specced ones.
Leopard/Snow Leopard improved on the previous version's 30 or so, but 90 is unthinkable.
The published Apple limits seem to be pulled out of a hat. When we challenged them, they laughed 'Your mileage may vary'.All, Mac OS X (10.5.7)
Currently Being ModeratedMar 16, 2011 7:43 AM (in response to Richard Cartledge)Look to either disk bandwidth, or to network bandwidth.
CPU and memory aren't a huge part of serving blocks and files.
The (un)likelihood of locality of reference among the clients probably doesn't warrant bug server I/O caches, either.
Your approach of adding additional low-spec Xserve servers has spread your load, which implies your disks might not be fast enough, or the network link into your server wasn't fast enough.
Currently Being ModeratedMar 16, 2011 10:42 AM (in response to Jeff Peach)You are running 10.6.6 server correct? Are the clients running the same?
On the main afp server how many connections do you have right now?
Do you auto mount network shares?Xserve, Mac OS X (10.6.5), 2.26ghz Quad Core
Currently Being ModeratedMar 16, 2011 11:43 AM (in response to ClassicII)Yes, 10.6.6 server.
Yes, almost all the clients are Intel 10.6.6 imacs (a few rogue emacs but not many)
Right now there are 88 users
Yes, we auto mount three shares, the home folders locations.Intel Imac, Mac OS X (10.6.6), Lab- Intel iMacs
Currently Being ModeratedMar 16, 2011 1:33 PM (in response to Jeff Peach)When you have lets say 40 connections how is the speed?
On the main afp home folders server are you running the 1 or 2 tb sata drives with a raid card and raid 5 or 0?Xserve, Mac OS X (10.6.5), 2.26ghz Quad Core
Currently Being ModeratedMar 16, 2011 2:32 PM (in response to ClassicII)The speed is good most of the time, all day. We have about 400-500 logons every day and it usually works pretty well.
The afp home folders are standard Apple 1 terabyte drives directly in the bays. Connection is SAS?Intel Imac, Mac OS X (10.6.6), Lab- Intel iMacs