rrdtool 1.3.8: RRDs::update do no update mtime RHEL 5.1 (Tikanga) ??

[Ole Bjørn Hessen]

Hello,

I've compiled rrdtool 1.3.8 on an Linux RHEL 5.1 (Tikanga) kernel
version 2.6.18-92.1.18.el5 out of the box using only the --prefix
option.

        |rrdtool config.status 1.3.8
        |configured by ./configure, generated by GNU Autoconf 2.63,
        |  with options \"'--prefix=/local/net/arch/linux_x86_64/encap/rrdtool-1.3.8'\"

Unfortunately, it seems like mtime does not get updated.

ls(1) reports that files was last updated on "Oct 16 09:30" but strace
shows that the files is beeing updated. Also rrdtool fetch shows that
the content has been updated. The problem seems to be that mtime is not
updated.

An example file /export/batch-rrd4/interface/54/14654.rrd

               ls -slt /export/batch-rrd4/interface/54/14654.rrd
               6376 -rw-rw-r-- 1 tiadm tiadm 6515984 Oct 16 09:30 /export/batch-rrd4/interface/54/14654.rrd
strace -tt:

11:45:09.732496 stat("/export/batch-rrd4/interface/54/14654.rrd", {st_mode=S_IFREG|0664, st_size=6515984, ...}) = 0
11:45:09.732586 open("/export/batch-rrd4/interface/54/14654.rrd", O_RDWR) = 7
11:45:09.732637 fstat(7, {st_mode=S_IFREG|0664, st_size=6515984, ...}) = 0
11:45:09.732697 fadvise64(7, 0, 0, POSIX_FADV_RANDOM) = 0
11:45:09.732737 mmap(NULL, 6515984, PROT_READ|PROT_WRITE, MAP_SHARED, 7, 0) = 0x2aaab05a4000
11:45:09.732780 madvise(0x2aaab05a4000, 6515984, 0x1 /* MADV_??? */) = 0
11:45:09.732819 madvise(0x2aaab05a4000, 128, MADV_SEQUENTIAL|0x1) = 0
11:45:09.732862 madvise(0x2aaab05a4000, 7680, MADV_SEQUENTIAL|0x1) = 0
11:45:09.732900 madvise(0x2aaab05a5000, 600, MADV_SEQUENTIAL|0x1) = 0
11:45:09.732938 madvise(0x2aaab05a6000, 16, MADV_SEQUENTIAL|0x1) = 0
11:45:09.732982 fcntl(7, F_SETLK, {type=F_WRLCK, whence=SEEK_SET, start=0, len=0}) = 0
11:45:09.733136 msync(0x2aaab05a4000, 6515984, MS_ASYNC) = 0
11:45:09.733174 munmap(0x2aaab05a4000, 6515984) = 0
11:45:09.733219 close(7)                = 0

There are no fancy mount options - just a simple ext3 rw.

    batch-rrd4(root) ~ 724# mount | grep batch-rrd4
    /dev/mapper/vg00-rrd on /export/batch-rrd4 type ext3 (rw)
    /export/batch-rrd4 on /local/net/mnt/batch-rrd4 type none (rw,bind)

Is this a simple linux bug on an RHEL 5.1 "old kernel" ?

Ole Bjørn Hessen,
NMS-IP
Telenor


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[Bernhard Reutner-Fischer]

On Tue, Oct 27, 2009 at 12:04:29PM +0100, Ole Bj�rn Hessen wrote:
>
>Hello,
>
>I've compiled rrdtool 1.3.8 on an Linux RHEL 5.1 (Tikanga) kernel
>version 2.6.18-92.1.18.el5 out of the box using only the --prefix
>option.

>There are no fancy mount options - just a simple ext3 rw.
>
>    batch-rrd4(root) ~ 724# mount | grep batch-rrd4
>    /dev/mapper/vg00-rrd on /export/batch-rrd4 type ext3 (rw)
>    /export/batch-rrd4 on /local/net/mnt/batch-rrd4 type none (rw,bind)
>
>Is this a simple linux bug on an RHEL 5.1 "old kernel" ?

This is a known bug on (old) redhat kernels, but configure should have
detected this bug and enabled a workaround. See (just a guess):
$ grep -A5 -B5 mmap config.log

It should show a probe for buggy mmap behaviour not updating mtime..

PS: IIRC 1.3.9 was released recently and contains some bugfixes, so i
recommend you use that if you compile it anyway.

HTH,

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