[Samba] Vista performance (uggh)

samba at lists.rupa.com samba at lists.rupa.com
Thu Oct 18 14:57:26 GMT 2007


Issue: Vista reads slowly from a samba server.  This appears to pop up
periodically here and elsewhere.

My samba.conf file has:

[homes]
 ...
 vfs objects = readahead

 As suggested elsewhere.

Writes are approximately 17-18MB/s which is acceptable.  Reads are in
the 8MB/s range which is appalingly slow.  Using linux smbclient and
windows XP clients I can read at 25+MB/s.  I've enabled vfs objects =
readahead to get better performance in vista.

The biggest difference I notice between vista and other clients is that
the %iowait is MUCH higher than with the other clients.  Logs show the
readahead module being loaded but I have no idea if it is actually doing
anything.

[2007/10/18 08:24:48, 2] lib/module.c:do_smb_load_module(64)
  Module '/usr/lib/samba/vfs/readahead.so' loaded


Server Config:

CPU: Amd Athlon 2600+
Ram: 1G
Disk: software raid5 across 5 250G ide drives each on dedicated channels
Kernel: Linux shakti 2.6.22 #1 SMP Wed Oct 17 15:32:01 CDT 2007 i686
GNU/Linux
Distro: debian etch

Network: Gigabit (though cheapo)

Any suggestions on where to go from here?

iostat 5 output for the physical devices below:

Using a new quad core running Vista client on gigabit
  - Reads at 8MB/s

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           2.81    0.00    9.62   73.95    0.00   13.63

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
hda              51.10      3033.27        20.84      15136        104
hde              53.91      3028.46        16.03      15112         80
hdg              49.90      2993.19        19.24      14936         96
hdi              47.49      3036.47         6.41      15152         32
hdk              49.30      2993.19        14.43      14936         72


Using a midrange Laptop running Windows XP on gigabit
  - Reads at 20MB/s

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           3.80    0.00   23.80   14.20    0.00   58.20

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
hda             199.80      8366.40        25.60      41832        128
hde             187.20      8380.80         8.00      41904         40
hdg             190.80      8377.60         9.60      41888         48
hdi             178.20      8376.00        16.00      41880         80
hdk             188.80      8377.60        20.80      41888        104


Using same host, smbclient, writing to a firewire drive
  - Reads at 26MB/s

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           7.58    0.00   38.92   30.74    0.00   22.75

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
hda             224.75      8693.01        20.76      43552        104
hde             214.37      8713.77        12.77      43656         64
hdg             212.97      8657.88        19.16      43376         96
hdi             195.61      8629.14        23.95      43232        120
hdk             197.01      8688.22        22.36      43528        112

Using dd to firewire drive
  - Reads at 27MB/s

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           6.40    0.00   59.40   34.20    0.00    0.00

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
hda             310.80     12844.80        17.60      64224         88
hde             317.80     12820.80         9.60      64104         48
hdg             308.60     12779.20        14.40      63896         72
hdi             294.00     12779.20         9.60      63896         48
hdk             294.80     12796.80        19.20      63984         96



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