I/O barriers and LVM

Posted Apr 1, 2009 7:11 UTC (Wed) by TRS-80 (guest, #1804)
Parent article: That massive filesystem thread

Looks like LVM finally got support for barriers in 2.6.29 (a year after first submitted) although only for linear targets.

I/O barriers and LVM

Posted Apr 1, 2009 13:40 UTC (Wed) by quotemstr (subscriber, #45331) [Link] (2 responses)

Nifty; thanks. This change alone is making me consider using a kernel.org kernel, something I haven't done in years.

I/O barriers and LVM

Posted Apr 1, 2009 19:03 UTC (Wed) by sbergman27 (guest, #10767) [Link] (1 responses)

"""
This change alone is making me consider using a kernel.org kernel, something I haven't done in years.
"""

Are you saying that distro kernels already do this? If so, I'm not suggesting that you are wrong. Just interested in more info.

I/O barriers and LVM

Posted Apr 1, 2009 19:08 UTC (Wed) by quotemstr (subscriber, #45331) [Link]

No, they don't do this. LVM's lack of barrier support has resulted in my not using LVM in some circumstances. If kernel.org kernels grow LVM barrier support and are otherwise stable, it might be worth using them until distribution kernels are updated to include the functionality.

I/O barriers and LVM

Posted Apr 1, 2009 13:44 UTC (Wed) by masoncl (subscriber, #47138) [Link]

Unfortunately, they don't actually get the barriers down to the device. There's a bug in the implementation...hopefully it'll get fixed up in 2.6.30 and then backported for 2.6.29-stable

(Credit to Eric Sandeen for tracking it down).