Hi Andy,
I know that the olbd doesn't support more than 64 server olbd's per manager
(for >64 you suggest that people group them in groups of 64 hierarchically),
but I think there might be a bug for >32 data servers.
I setup 32 data servers plus a redirector and spread some files around
on the 32 data servers. Here everything seems to work: when I access the
files via the redirector I'm always redirected to the right place.
I then stopped the servers on the redirector, started 6 additional data
servers (for a total of 38) and restarted the xrootd and olbd on the
redirector. With that setup I sometimes find that the client is redirected to
a machine which doesn't have the file. In the particular example I looked
at it was directed to tori0291 when tori0254 actually has the file.
I looked at the order in which the server olbd's logged in to the manager
olbd (see (a) below) and a pattern jumps out: the data is on the 5th server
while the client was redirected to the 37th (=32+5). Is there perhaps some bit
shifting or similar set for 32 instead of 64 somewhere? I'm not sure anyone
has yet tried >32 servers. (SLAC currently has 30 in the xrootd pool.)
(This was with the HEAD of CVS as of right now.)
Pete
(a)
1 tori0287.slac.stanford.edu
2 tori0288.slac.stanford.edu
3 tori0289.slac.stanford.edu
4 tori0260.slac.stanford.edu
5 tori0254.slac.stanford.edu **
6 tori0282.slac.stanford.edu
7 tori0252.slac.stanford.edu
8 tori0277.slac.stanford.edu
9 tori0272.slac.stanford.edu
10 tori0262.slac.stanford.edu
11 tori0255.slac.stanford.edu
12 tori0275.slac.stanford.edu
13 tori0280.slac.stanford.edu
14 tori0278.slac.stanford.edu
15 tori0267.slac.stanford.edu
16 tori0251.slac.stanford.edu
17 tori0284.slac.stanford.edu
18 tori0276.slac.stanford.edu
19 tori0286.slac.stanford.edu
20 tori0263.slac.stanford.edu
21 tori0253.slac.stanford.edu
22 tori0264.slac.stanford.edu
23 tori0281.slac.stanford.edu
24 tori0283.slac.stanford.edu
25 tori0274.slac.stanford.edu
26 tori0258.slac.stanford.edu
27 tori0270.slac.stanford.edu
28 tori0257.slac.stanford.edu
29 tori0271.slac.stanford.edu
30 tori0268.slac.stanford.edu
31 tori0265.slac.stanford.edu
32 tori0259.slac.stanford.edu
33 tori0266.slac.stanford.edu
34 tori0285.slac.stanford.edu
35 tori0261.slac.stanford.edu
36 tori0290.slac.stanford.edu
37 tori0291.slac.stanford.edu **
38 tori0292.slac.stanford.edu
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Peter Elmer E-mail: [log in to unmask] Phone: +41 (22) 767-4644
Address: CERN Division PPE, Bat. 32 2C-14, CH-1211 Geneva 23, Switzerland
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