Comment 9 for bug 570805
Revision history for this message
| Dmitry Potapov (dpotapov) wrote Re: [regression] dpkg fsync cause massive regression in Ubuntu Server and Alternate installation times | #9 |
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(Get the code!)
The explanation in the release notes is confusing. First of all, as Jakob wrote above, ext4 starting with 2.6.30 provides similar behavior to ext3 with data=ordered. So, it is not clear why fsync() is necessary on ext4, but not on ext3.
More importantly, the default mode for ext3 was changed to data=writeback in 2.6.30, which does not provide the same guarantee as "ordered". Even if the default was changed to be "ordered" in Ubuntu kernel, users still may use an upstream kernel or change the mode to "writeback" on ext3, because the "ordered" mode has horrible latency (20 times or more than "writeback"). Does it mean that anyone running ext3 with data=writeback can face corruption of their package repository?