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Sometimes NSCD die itself and DNS resolving doesn't occur properly. How can we avoid NSCD for DNS and is there any disadvantage to bypass it? |
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Answer» NSCD means Name Service CACHE Daemon which provides a cache for the most common name service requests. When resolving a USER, group, service the process will first TRY to connect to the NSCD socket (something like /var/run/nscd/socket2). If NSCD died, then the connection will fail and NSCD won't be used for same and that should not be a problem. If NSCD in a hung state, then the connection may hang or succeed. If this succeeds then the client will send the request. Now, we can configure NSCD to disable caching for any type of the database (for instance by having enable-cache hosts no in the /etc/nscd.conf for hosts database). However, if NSCD is in a hung state, it may not be able to even give that simply won't do the answer, so that won't necessarily help. NSCD is a caching daemon, it's meant to improve the performance. DISABLING it would POTENTIALLY make those lookups slower. However, that's only true for some kind of databases. For the instance, if user/service/group databases are only in small files (/etc/passwd, /etc/group, /etc/services), then using NSCD for those will probably bring little benefit if any. NSCD will be very useful for the host's database. |
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