CNFS buffers bigger than 2 GB under Linux ?

bill davidsen davidsen at tmr.com
Thu Mar 21 20:51:31 UTC 2002


In article <20020318123323.I10749 at aegir.fw.belnet.be>,
Antoine Delvaux  <antoine.delvaux at belnet.be> wrote:
| 
| > > Yes, I'm using raw devices.
| >=20
| > > I wanted to use a single raw devices as under it lies a RAID stripping
| > > setup which already gives me the speed that I want.  I don't need much
| > > flexibility neither as this server will be a feed only with nearly no
| > > backlog and so only one article spool.
| >=20
| > Well, you can just use large disk files.
| 
| Yes, but this will slow down innd I think, no ?  That's why I wanted to=20
| use raw devices.

  Looking at the load profile, I can't see that CPU or disk is a
limitation using large files. If you are trying to improve your freenix
every ms counts, otherwise I bet you can't even measure the effect.

time   load free buffs swap pgin pgou dk0 dk1 dk2 dk3 ipkt opkt  int  ctx   usr sys idl  i_netK  o_netK
15.254 0.32  5.8  2087  0.0   64 1675  19   5   6   6 1521 1396 2075 2155     1   4  95  1621.7  1135.6
15.304 0.20  6.4  2088  0.0   64 1642  20   6   5   5 1488 1379 2040 2098     1   4  95  1573.5  1119.4
15.354 0.36  5.6  2086  0.0   66 1602  20   6   5   6 1439 1304 1981 2076     1   4  95  1548.8  1016.5
15.404 0.24  5.3  2087  0.0   69 1651  20   6   5   6 1510 1408 2068 2109     1   4  95  1590.6  1152.9
15.454 0.08  5.2  2088  0.0   56 1231  17   4   4   4 1426 1753 1879 1595     0   4  96  1106.8  1892.0
15.504 0.10  5.0  2089  0.0   58 1165  17   4   4   4 1408 1742 1866 1582     0   3  97  1094.4  1875.1
15.554 0.06  7.1  2086  0.0   56 1216  17   4   4   4 1514 1844 1986 1710     0   4  96  1205.8  1980.0
15.604 0.11  5.0  2083  0.0   72 1400  20   5   5   5 1784 2164 2325 1984     1   5  94  1427.2  2333.0
15.655 0.04  5.5  2084  0.0   78 1579  21   5   5   5 1977 2373 2554 2190     1   5  94  1609.3  2568.6
15.705 0.17  5.3  2081  0.0   85 1561  23   5   6   5 1866 2353 2412 1993     0   5  95  1409.8  2623.2
15.755 0.40  6.5  2082  0.0   64 1040  17   3   4   4 1272 1589 1682 1433     0   3  97   977.2  1723.7

| But does anybody knows where the 2GB limitation for rw devices comes from=
| =20
| ?  INND or the Linux kernel ?

  From using a raw device... call it a suboptimal configuration choice ;-)
-- 
bill davidsen <davidsen at tmr.com>
  CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.


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