==> Regarding [autofs] stat of /users/no-such-user takes 15 seconds; Brian Long
<[EMAIL PROTECTED]> adds:
brilong> I have an auto.master deployed to thousands of hosts and it looks
brilong> like this:
brilong> /misc /etc/auto.misc --timeout=60 /auto /etc/auto.indirect
brilong> rsize=32768,wsize=32768,tcp /users auto_home
brilong> rw,hard,intr,rsize=32768,wsize=32768,tcp
brilong> As you can see, /users comes from NIS auto.home map. In our case,
brilong> auto.home contains over 34,000 entries. I've noticed in RHEL 3 U5
brilong> and beyond (autofs-4.1.3-130), trying to stat (ls)
brilong> /users/no-such-user takes roughly 12-15 seconds. In RHEL 3 U3
brilong> (autofs-4.1.3-12), it returns immediately. This is a regression
brilong> in my opinion.
brilong> After looking at tcpdump data, it appears automounter is
brilong> downloading the entire auto.home map when it fails to lookup
brilong> "no-such-user". This results in a > 700KB transfer from the NIS
brilong> server :(
brilong> In the older autofs version, it does NOT do this. I have opened a
brilong> Red Hat issue tracker (82760), but in parallel I wanted to ask
brilong> this list if this is known behavior and if there is any way I can
brilong> disable the download of the entire auto.home map using
brilong> /etc/sysconfig/autofs or auto.master options to the automount
brilong> program.
This is likely a side-effect of the cache expiry code. Try this patch on
for size.
-Jeff
--- autofs-4.1.3/modules/lookup_yp.c.orig 2005-11-22 10:40:57.000000000
-0500
+++ autofs-4.1.3/modules/lookup_yp.c 2005-11-22 10:44:16.000000000 -0500
@@ -224,7 +224,7 @@ int lookup_mount(const char *root, const
int key_len;
char *mapent;
int mapent_len;
- struct mapent_cache *me;
+ struct mapent_cache *me, *exists;
int ret;
time_t now = time(NULL);
time_t t_last_read;
@@ -240,7 +240,13 @@ int lookup_mount(const char *root, const
if (key_len > KEY_MAX_LEN)
return 1;
- /* check map and if change is detected re-read map */
+ /*
+ * check map and if change is detected re-read map
+ */
+
+ /* First check to see if this entry exists in the cache */
+ exists = cache_lookup(key);
+
ret = lookup_one(root, key, key_len, ctxt);
debug("ret = %d", ret);
@@ -270,8 +276,8 @@ int lookup_mount(const char *root, const
if (ap.type == LKP_INDIRECT)
lookup_wild(root, ctxt);
- /* Have parent update its map */
- if (t_last_read > ap.exp_runfreq)
+ /* Have parent update its map if the key existed before */
+ if (exists && t_last_read > ap.exp_runfreq)
kill(getppid(), SIGHUP);
}
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