Server Announcement, 2005-Nov-14

[Leaf]

Python features (Casino, Post Office, Message boards) are off-line until further notice.

Player files that have *not* been active for a year or more have been moved to a backup directory. Please contact a DM if you need access to one of these character(s).

These steps were taken to try and diagnose & troubleshoot the cause(s) of the player login lag that the server has been experiencing. The investigation is on-going.

[Aaron]

maybe try swapping the player directories to a new drive, and seeing how that works? of course if you dont have one lying around, it might be an expensive test...

[cavesomething]

unless the player files are stored on a stupid filesystem that suffers from fragmentation (like NTFS, FAT or reiser 4) then the read speed of the files won't be dependent on that, but primarily the speed of the drive, in that case hdparm would determine whether it were performing noticably below spec, and if it wasn't, switching to another drive using the same filesystem would make no noticable difference (and may hurt performance if you have a PATA drive where a slave is added to a channel that previously only had a master - although I'm fairly sure this isn't the case with mf).

[woo]

for the sake of argument leaf the command to test the hard drive would be:

#for the first IDE drive
hdparm -tT /dev/hda

#for the second IDE drive
hdparm -tT /dev/hdb

#first scsi drive
hdparm -tT /dev/sda

#second scsi drive
hdparm -tT /dev/sdb

You can get a list of drives (and partitions) with
fdisk -l

[Leaf]

The results....

# fdisk -l

Disk /dev/sda: 255 heads, 63 sectors, 9729 cylinders
Units = cylinders of 16065 * 512 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 9598 77095903+ 83 Linux
/dev/sda2 9599 9729 1052257+ 82 Linux swap

# hdparm -tT /dev/sda1
/dev/sda1:
Timing buffer-cache reads: 128 MB in 0.48 seconds =266.67 MB/sec
Timing buffered disk reads: 64 MB in 1.63 seconds = 39.26 MB/sec


# hdparm -tT /dev/sda2
/dev/sda2:
Timing buffer-cache reads: 128 MB in 0.50 seconds =256.00 MB/sec
Timing buffered disk reads: 64 MB in 2.53 seconds = 25.30 MB/sec

[Leaf]

unless the player files are stored on a stupid filesystem that suffers from fragmentation (like NTFS, FAT or reiser 4)

It's ext3

[cavesomething]

well then, quite clearly it isn't a hardware speed issue, the server should /not/ need to read anything like 39MB/s at login. (although, you seem to have quite a slow swap partition - outside edge of the disk maybe? - so it maybe that if the working set of that system is typically close to but not above the level at which swap is needed, that the swapping out and back in of parts of memory may be slow enough to offset the speed gains from having more memory for the file and data cache. Actually /proving/ that this is the case is probably far more effort than the result is worth.

A more useful attempt at debugging would be to run the server through strace, and try and determine what files are being accessed, then try and figure out /why/ they need to be accessed.

However, this would require restarting the server, and would both slow it down (which is the problem to begin with) and give a /lot/ of information.

[bencha]

The main disk access ( and network traffic ) at player login isn't the player saved files, it's the dowload of all the images files needed. And if the client is configured with 'download all image information', it may be even worse.

that's why we should advertise for pocket reality chests to keep homes clean

[cavesomething]

the image files server side are currently about 4 MB -not enough to explain what is being seen.

[Leaf]

Python features (Casino, Post Office, Message boards) are off-line until further notice.

After approximately 5 weeks of testing, the Python features are officially back in place now.