On Thursday, September 01, 2016 08:41:39 AM Michael Mol wrote: > On Wednesday, August 31, 2016 11:45:15 PM Alan McKinnon wrote: > > On 31/08/2016 17:25, Grant wrote: > > >> Which NTFS system are you using? > > >> > > >> ntfs kernel module? It's quite dodgy and unsafe with writes > > >> ntfs-ng on fuse? I find that one quite solid > > > > > > I'm using ntfs-ng as opposed to the kernel option(s). > > > > I'm offering 10 to 1 odds that your problems came from ... one that you > > yanked too soon > > (pardon the in-line snip, while I get on my soap box) > > The likelihood of this happening can be greatly reduced by setting > vm.dirty_bytes to something like 2097125 and vm.dirty_background_bytes to > something like 1048576. This prevents the kernel from queuing up as much > data for sending to disk. The application doing the copy or write will > normally report "complete" long before writes to slow media are > actually...complete. Setting vm.dirty_bytes to something low prevents the > kernel's backlog of data from getting so long. > > vm.dirty_bytes has another, closely-related setting, vm.dirty_bytes_ratio. > vm.dirty_bytes_ratio is a percentage of RAM that is used for dirty bytes. If > vm.dirty_bytes_ratio is set, vm.dirty_bytes will read 0. If vm.dirty_bytes > is set, vm.dirty_bytes_ratio will read 0. > > The default is for vm.dirty_bytes_ratio to be 20, which means up to 20% of > your memory can find itself used as a write buffer for data on its way to a > filesystem. On a system with only 2GiB of RAM, that's 409MiB of data that > the kernel may still be waiting to push through the filesystem layer! If > you're writing to, say, a class 10 SDHC card, the data may not be at rest > for another 40s after the application reports the copy operation is > complete! > > If you've got a system with 8GiB of memory, multiply all that by four. > > The defaults for vm.dirty_bytes and vm.dirty_background_bytes are, IMO, > badly broken and an insidious source of problems for both regular Linux > users and system administrators.
I would prefer to be able to have different settings per disk. Swappable drives like USB, I would put small numbers. But for built-in drives, I'd prefer to keep default values or tuned to the actual drive. -- Joost
