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Diffstat (limited to 'FAQ')
| -rw-r--r-- | FAQ | 28 |
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diff --git a/FAQ b/FAQ index a3fdddee52..a3d3b5a152 100644 --- a/FAQ +++ b/FAQ @@ -93,6 +93,7 @@ please let me know. 2.23. I just upgraded my Linux system to glibc and now I get errors whenever I try to link any program. 2.24. When I use nscd the machine freezes. +2.25. I need lots of open files. What do I have to do? 3. Source and binary incompatibilities, and what to do about them @@ -943,6 +944,33 @@ If you need nscd, you have to use a 2.1 kernel. Note that I have at this point no information about any other platform. + +2.25. I need lots of open files. What do I have to do? + +{AJ} This is at first a kernel issue. The kernel defines limits with +OPEN_MAX the number of simultaneous open files and with FD_SETSIZE the +number of used file descriptors. You need to change these values in your +kernel and recompile the kernel so that the kernel allows to use more open +files. You don't necessarily need to recompile the GNU C library since the +only place where OPEN_MAX and FD_SETSIZE is really needed in the library +itself is the size of fd_set which is used by select. + +The GNU C library is now (nearly) select free. This means it internally has +no limits imposed by the `fd_set' type. Instead almost all places where the +functionality is needed the `poll' function is used. + +If you increase the number of file descriptors in the kernel you don't need +to recompile the C library. The remaining select calls are in the RPC code. +If your RPC daemons don't need more than FD_SETSIZE file descriptors, you +don't need to change anything at all. + +{UD} You can always get the maximum number of file descriptors a process is +allowed to have open at any time using + + number = sysconf (_SC_OPEN_MAX); + +This will work even if the kernel limits change. + . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |