What is the patch number?? thanks Mace --- Patrick Spinler <[EMAIL PROTECTED]> wrote:
> -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Mark Perry wrote: > | > | The Linux Kernel defaults to not using "barriers", > but SLES has a patch > | to enable it by default. > > Just a couple of thoughts, and information from the > article. > > Note the default above is a filesystem flag. You > can turn this on in > all your mounts by hand, also. > > However, be aware this flag is valueless if you're > running a filesystem > on top of LVM. > > This is what the article has to say about it: > > | It turns out that the "getting away with it" > factor is not just luck. > Ted Ts'o explains what's going on: the journal on > ext3/ext4 filesystems > is normally contiguous on the physical media. The > filesystem code tries > to create it that way, and, since the journal is > normally created at the > same time as the filesystem itself, contiguous space > is easy to come by. > Keeping the journal together will be good for > performance, but it also > helps to prevent reordering. In normal usage, the > commit record will > land on the block just after the rest of the journal > data, so there is > no reason for the drive to reorder things. The > commit record will > naturally be written just after all of the other > journal log data has > made it to the media. > | > | That said, nobody is foolish enough to claim that > things will always > happen that way. Disk drives have a certain > well-documented tendency to > stop cooperating at inopportune times. Beyond that, > the journal is > essentially a circular buffer; when a transaction > wraps off the end, the > commit record may be on an earlier block than some > of the journal data. > And so on. So the potential for corruption is always > there; in fact, > Chris Mason has a torture-test program which can > make it happen fairly > reliably. There can be no doubt that running without > barriers is less > safe than using them. > | > > Often, once these issues come to light in the linux > kernel community, > some solutions or another follows. I'm rather > hoping that will also be > the case for this one. > > - -- Pat > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.7 (Darwin) > Comment: Using GnuPG with Mozilla - > http://enigmail.mozdev.org > > iD8DBQFIPBnpNObCqA8uBswRAkcoAJ9/PL0hhnzy2tP5TmWVjM1M4r9KiQCeM3Xv > VPrO6T4Pu5pPByRlQeQHzaI= > =4FnQ > -----END PGP SIGNATURE----- > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access > instructions, > send email to [EMAIL PROTECTED] with the > message: INFO LINUX-390 or visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 > ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
