Hi - I had a read of the Redhat documentation on cache sizes and tuning and tried tweaking one of my servers as it was setup with the default. The server is a Fedora 10 box with 4GB of RAM so I decided to setup the cache as: nsslapd-cachememsize = 3145728000 (3GB) nsslapd-dbcachesize = 3670016000 (3.5GB) But when I restart I get the message: [01/Apr/2010:13:56:30 +0100] - WARNING -- Possible CONFIGURATION ERROR -- cachesize (2072199168) may be configured to use more than the available physical memory. [01/Apr/2010:13:56:30 +0100] - WARNING---Likely CONFIGURATION ERROR---dbcachesize is configured to use more than the available physical memory, decreased to the largest available size (2072199168 bytes). [01/Apr/2010:13:56:30 +0100] - I'm resizing my cache now...cache was 2072203264 and is now 2072199168 Is there a limit of 2GB on the cache sizes? The server has 4GB memory.. I then put the settings down lower to: nsslapd-cachememsize = 1153433600 (1.1 GB) nsslapd-dbcachesize = 1677721600 (1.6 GB) I then hit it with some big queries to load up the cache and now I get: [01/Apr/2010:14:34:15 +0100] - libdb: txn_checkpoint: failed to flush the buffer cache: Cannot allocate memory [01/Apr/2010:14:34:15 +0100] - Serious Error---Failed to checkpoint database, err=12 (Cannot allocate memory) [01/Apr/2010:14:34:15 +0100] - libdb: malloc: 3145764: Cannot allocate memory [01/Apr/2010:14:34:15 +0100] - libdb: txn_checkpoint: failed to flush the buffer cache: Cannot allocate memory [01/Apr/2010:14:34:15 +0100] memory allocator - calloc of 8194 elems of 4 bytes failed; OS error 12 (Cannot allocate memory) The server has probably allocated all available virtual memory. When that happened top was reporting the slapd process only using %40 memory and there is nothing else running on this server. I was trying to do some tuning as these servers are worked quite hard and the "Entry Cache hits" was showing as 0 - I would of expected some hits even with a smallish cache? Thanks. Jim.
