| 1 |
Am 22.03.2011 09:13, schrieb Mr. Jarry: |
| 2 |
> Thanks for replies. As I had expected, they brought even more |
| 3 |
> uncertainty then I had before... :-) |
| 4 |
> |
| 5 |
> ext3/4: |
| 6 |
> I excluded them because as I understand, they do not support |
| 7 |
> snapshots (only with lvm, which I do not use, and I've hreard |
| 8 |
> snapshots in lvm are not very effective, or something like that). |
| 9 |
> Next minus-point, I tried resizing of ext3/lvm once in the past |
| 10 |
> and remember it was a real pain in a**... |
| 11 |
> |
| 12 |
|
| 13 |
Neil already pointed out that resizing is plain easy. Increasing the |
| 14 |
size online is a matter of seconds. Shrinking needs to be done offline |
| 15 |
after an `e2fsck -f` but is no problem, either. |
| 16 |
|
| 17 |
> reiserfs/reiser4: |
| 18 |
> Future of these fs seems to be somehow vague, at least to me. |
| 19 |
> And I do not know if it can handle snaphosts and resizing. |
| 20 |
> |
| 21 |
|
| 22 |
Reiserfs-3 supports increasing the size but not shrinking (AFAIK). |
| 23 |
Performance characteristics are similar to Ext3 in this regard. |
| 24 |
|
| 25 |
> xfs & power-off: |
| 26 |
> I have always thought, journaling is there to prevent data |
| 27 |
> loss during unexpected power-off. And now I read I could |
| 28 |
> loose data even with journaled fs...? |
| 29 |
> |
| 30 |
|
| 31 |
Journalling is better suited for system crashes than power failures. |
| 32 |
Things get especially ugly when you think about write caches in HDDs or |
| 33 |
RAID controllers. |
| 34 |
|
| 35 |
Additionally, the main purpose of journalling is to protect the file |
| 36 |
system, not the data. Normally, journals only contain metadata changes |
| 37 |
like space allocations to files but not the actual data written to it. |
| 38 |
Even good old Ext3 might put random junk at the end of your files when |
| 39 |
it is mounted with journal=writeback during a crash. |
| 40 |
|
| 41 |
This is basically a speed/security tradeoff. When you read up about the |
| 42 |
various journal options for Ext3, you will understand it better. |
| 43 |
|
| 44 |
> jfs & power-off: |
| 45 |
> the same. How is it possible, I could loose data with such |
| 46 |
> a mature journaled filesystem during power-off? |
| 47 |
> |
| 48 |
> btrfs: |
| 49 |
> never heard of it. Is it stable enough to be used? I just |
| 50 |
> checkt man-page of "mount", and it does not show btrfs |
| 51 |
> as supported filesystem... |
| 52 |
> |
| 53 |
|
| 54 |
Wikipedia has information about it. Basically, it will be replacement of |
| 55 |
Ext4. |
| 56 |
|
| 57 |
Hope this helps, |
| 58 |
Florian Philipp |
Archives