Thanks for good comments.
>> Is the OP using Oracle Linux? > > He didn't say. But he didn't say he WON'T be using oracle linux (or > other distro which supports btrfs) either. Plus the kernel can be > installed on top of RHEL/Centos 5 and 6, so he can easily choose > either the supported version, or the mainline version, each with its > own consequences. For further info: Nope, not using Oracle Linux. Then again, I'm reasonably distro agnostic. I'm also happy to compile my own kernels. And the system in question uses a HDD RAID and looks to be more IOPS bound rather than suffering actual IO data rate bound. The large directories certainly don't help! It's running postfix + courier-imap at the moment and I'm looking to revamp it for the gradually ever increasing workload. CPU and RAM usage is low on average. It serves 2x Gbit networks + internet users (3 NIC ports). Hence I'm considering the best way for an revamp/upgrade. SSDs would certainly help with the IOPS but I'm cautious about SSD wear-out for a system that constantly thrashes through a lot of data. I could just throw more disks at it to divide up the IO load. Multiple pairs of "HDD paired with SSD on md RAID 1 mirror" is a thought with ext4... bcache looks ideal to help but also looks too 'experimental'. And I was hoping that btrfs would help with handling the large directories and multi-user parallel accesses, especially so for being 'mirrored' by btrfs itself (at the filesystem level) across 4 disks for example. Thoughts welcomed. Is btrfs development at the 'optimising' stage now, or is it all still very much a 'work in progress'? Regards, Martin -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html