14.08.2016 19:20, Chris Murphy пишет: > > As an aside, I'm finding the size information for the data chunk in > 'fi us' confusing... > > The sample file system contains one file: > [root@f24s ~]# ls -lh /mnt/0 > total 1.4G > -rw-r--r--. 1 root root 1.4G Aug 13 19:24 > Fedora-Workstation-Live-x86_64-25-20160810.n.0.iso > > > [root@f24s ~]# btrfs fi us /mnt/0 > Overall: > Device size: 400.00GiB > Device allocated: 8.03GiB > Device unallocated: 391.97GiB > Device missing: 0.00B > Used: 2.66GiB > Free (estimated): 196.66GiB (min: 196.66GiB) > Data ratio: 2.00 > Metadata ratio: 2.00 > Global reserve: 16.00MiB (used: 0.00B) > > ## "Device size" is total volume or pool size, "Used" shows actual > usage accounting for the replication of raid1, and yet "Free" shows > 1/2. This can't work long term as by the time I have 100GiB in the > volume, Used will report 200Gib while Free will report 100GiB for a > total of 300GiB which does not match the device size. So that's a bug > in my opinion. > Well, it says "estimated". It shows how much you could possibly write using current allocation profile(s). There is no way to predict actual space usage if you mix allocation profiles. I agree that having single field that is referring to virtual capacity among fields showing physical consumption is confusing. > Data,RAID10: Size:2.00GiB, Used:1.33GiB > /dev/mapper/VG-1 512.00MiB > /dev/mapper/VG-2 512.00MiB > /dev/mapper/VG-3 512.00MiB > /dev/mapper/VG-4 512.00MiB > > ## The file is 1.4GiB but the Used reported is 1.33GiB? That's weird. I think this is difference between rounding done by ls and internal btrfs counting. I bet if you show size in KiB (or even 512B) you will get better match. > And now in this area the user is somehow expected to know that all of > these values are 1/2 their actual value due to the RAID10. I don't > like this inconsistency for one. But it's made worse by using the > secret decoder ring method of usage when it comes to individual device > allocations. Very clearly Size if really 4, and each device has a 1GiB > chunk. So why not say that? This is consistent with the earlier > "Device allocated" value of 8GiB. > > This looks like a bug in RAID10. In RAID1 output is consistent with Size showing virtual size and each disk allocated size matching it. This is openSUSE Tumbleweed with brfsprogs 4.7 and kernel 4.7. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
