* "Theodore Ts'o" <tytso@xxxxxxx> hat geschrieben: > On Thu, Oct 16, 2014 at 11:01:35PM +0200, Bodo Thiesen wrote: > > > > Since it never get's updated unless the file system is unmounted, it can > > only be used for a 24 hours test by mounting the file system now, > > unmounting it 24 hours from now and then taking the difference. > > It also gets updated if the file system syncfs(2) or sync(2) system > call. Then sync(1) doesn't call sync(2) ... wait ... # strace sync [...] sync() = 0 [...] hmmm ... So, why didn't the value get updated after writing some GB of data (dd for testing yesterday)? # sync # echo 3 > /proc/sys/vm/drop_caches # tune2fs -l /dev/sda | grep Lifetime Lifetime writes: 2503 GB # uptime 01:11:10 up 2 days, 22:26, 15 users, load average: 0.98, 0.99, 1.02 So, I guess you have to recheck the code for that statement because it really doesn't reflect reality. > But if you crash, any writes since the last syncfs(2), sync(2), > or umount(2) call on the file system can get lost, yes. "Will", not "can". >> Also the value is only available in granularity of 1 GB (plus minus >> 512MB) - at least in my case. > This is what dumpe2fs is currently using: > [printing prefixes] > What we are doing was deliberate, in an effort to display things in a > user-friendly fashion that was hopefully still useful. If you'd like > to propose something different, please send patches and I'll consider it. I quess a simple cmd line option "--raw-values" would be cool not only for dumpe2fs but tune2fs as well - that just switches off this - in fact not *that* bad - default behavior on explicit demand. So, if you're going to include such a patch for some[tm] tools, I'd be happy to do it, just give me some time for that ;) >> I did test /sys/fs/ext4/sda/lifetime_write_kbytes now, that seems to be >> somewhat less bogus, so *that* might actuall be usable for the 24 hours >> test. But I wasn't talking about that when I said, that this lifetime >> thing is bogus. > Bogus is in the eye of the beholder. It's not perfect, and if your > system is regularly crashing, then it will be much less perfect. It was because of the rcu-bug which I didn't know and I did actually blame fglrx for the crashes - which was - as it turned out - not fair. My system is table now. (the uptime of almost 3 days was a deliberate shut down ;) > If it's not helpful enough for your use case, don't use it. Oh, actually, I don't need that value at all, Jelle needs it. But yes, it seems good enough for his use case. But he has to use the sys interface not tune2fs/dumpe2fs for the lifetime writes value. Regars, Bodo _______________________________________________ Ext3-users mailing list Ext3-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/ext3-users
