<div dir="ltr"><div><div><div>Here are the answers to your questions </div>1. fsck does not report any error and the file contained inside the FS is definitely greater than the allocatable LV size # fsck.ext4 -f -C0 /dev/virtp/vol01 e2fsck 1.43-WIP (15-Mar-2016) Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information /dev/virtp/vol01: 12/65536 files (8.3% non-contiguous), 30492/262144 blocks </div>2. Size of the file # du -hs fil 69M fil </div><div>(please note here that the LV virtual size is 1G but the parent pool size is just 40M I expect the file not to exceed 40M at any cost.) </div>3. lvs # lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert virtpool virtp twi-aotzD- 40.00m 100.00 1.37 vol01 virtp Vwi-aotz-- 1.00g virtpool <div> </div><div>You can do this on any virtual machine. I use qemu with virtio back-end. </div></div><div class="gmail_extra"> <div class="gmail_quote">On Tue, May 3, 2016 at 11:54 AM, Zdenek Kabelac <<a href="mailto:zkabelac@redhat.com" target="_blank">zkabelac@redhat.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On 3.5.2016 08:59, Bhasker C V wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Does this mean the ext4 is showing wrong information. The file is reported being 90+MB but in actuality the size is less in the FS ? This is quite ok because it is just that file system being affected. I was however concerned that the file in this FS might have overwritten other LV data since the file is showing bigger than the volume size. </blockquote> I've no idea what 'ext4' is showing you, but if you have i.e. 100M filesystem size, you could still have there e.g. 1TB file. Experience the magic: 'truncate -s 1T myfirst1TBfile' As you can see 'ext4' is doing it's own over-provisioning with 'hole' files. The only important bits are: - is the filesystem consistent ? - is 'fsck' not reporting any error ? What's the 'real' size you get with 'du myfirst1TBfile' or your wrong file ? Somehow I don't believe you can get i.e. 90+MB 'du' size with 10MB filesystem size and 'fsck' would not report any problem. <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> I will try this using BTRFS. </blockquote> For what exactly ?? Regard Zdenek <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> On Fri, Apr 29, 2016 at 10:13 AM, Zdenek Kabelac <<a href="mailto:zkabelac@redhat.com" target="_blank">zkabelac@redhat.com</a> <div><div class="h5"> <mailto:<a href="mailto:zkabelac@redhat.com" target="_blank">zkabelac@redhat.com</a>>> wrote: On 28.4.2016 16:36, Bhasker C V wrote: Zdenek, Thanks. Here I am just filling it up with random data and so I am not concerned about data integrity You are right, I did get page lost during write errors in the kernel The question however is even after reboot and doing several fsck of the ext4fs the file size "occupied" is more than the pool size. How is this ? I agree that data may be corrupted, but there *is* some data and this must be saved somewhere. Why is this "somewhere" exceeding the pool size ? Hi Few key principles - 1. You should always mount extX fs with errors=remount-ro (tune2fs,mount) 2. There are few data={} modes ensuring various degree of data integrity, An case you really care about data integrity here - switch to 'journal' mode at price of lower speed. Default ordered mode might show this. (i.e. it's the very same behavior as you would have seen with failing hdd) 3. Do not continue using thin-pool when it's full :) 4. We do miss more configurable policies with thin-pools. i.e. do plan to instantiate 'error' target for writes in the case pool gets full - so ALL writes will be errored - as of now - writes to provisioned blocks may cause further filesystem confusion - that's why 'remount-ro' is rather mandatory - xfs is recently being enhanced to provide similar logic. Regards Zdenek _______________________________________________ linux-lvm mailing list </div></div> <a href="mailto:linux-lvm@redhat.com" target="_blank">linux-lvm@redhat.com</a> <mailto:<a href="mailto:linux-lvm@redhat.com" target="_blank">linux-lvm@redhat.com</a>> <a href="https://www.redhat.com/mailman/listinfo/linux-lvm" rel="noreferrer" target="_blank">https://www.redhat.com/mailman/listinfo/linux-lvm</a> read the LVM HOW-TO at <a href="http://tldp.org/HOWTO/LVM-HOWTO/" rel="noreferrer" target="_blank">http://tldp.org/HOWTO/LVM-HOWTO/</a> _______________________________________________ linux-lvm mailing list <a href="mailto:linux-lvm@redhat.com" target="_blank">linux-lvm@redhat.com</a> <a href="https://www.redhat.com/mailman/listinfo/linux-lvm" rel="noreferrer" target="_blank">https://www.redhat.com/mailman/listinfo/linux-lvm</a> read the LVM HOW-TO at <a href="http://tldp.org/HOWTO/LVM-HOWTO/" rel="noreferrer" target="_blank">http://tldp.org/HOWTO/LVM-HOWTO/</a> </blockquote><div class="HOEnZb"><div class="h5"> _______________________________________________ linux-lvm mailing list <a href="mailto:linux-lvm@redhat.com" target="_blank">linux-lvm@redhat.com</a> <a href="https://www.redhat.com/mailman/listinfo/linux-lvm" rel="noreferrer" target="_blank">https://www.redhat.com/mailman/listinfo/linux-lvm</a> read the LVM HOW-TO at <a href="http://tldp.org/HOWTO/LVM-HOWTO/" rel="noreferrer" target="_blank">http://tldp.org/HOWTO/LVM-HOWTO/</a> </div></div></blockquote></div> </div>