Rich Freeman wrote: > On Fri, May 22, 2020 at 11:32 AM Michael <confabul...@kintzios.com> wrote: >> An interesting article mentioning WD Red NAS drives which may actually be >> SMRs >> and how latency increases when cached writes need to be transferred into SMR >> blocks. > Yeah, there is a lot of background on this stuff. > > You should view a drive-managed SMR drive as basically a journaled > filesystem/database masquerading as a virtual drive. One where the > keys/filenames are LBAs, and all the files are 512 bytes long. :) > > Really even most spinning drives are this way due to the 4k physical > sectors, but this is something much easier to deal with and handled by > the OS with aligned writes as much as possible. SSDs have similar > issues but again the impact isn't nearly as bad and is more easily > managed by the OS with TRIM/etc. > > A host-managed SMR drive operates much more like a physical drive, but > in this case the OS/application needs to be SMR-aware for performance > not to be absolutely terrible. >
The thing about the one I have now in use by LVM for /home, one is SMR and one is PMR. Even if the OS is aware, does it even know which drive the data is going to end up being stored on? I'm pretty sure since the PMR drive was in use before the SMR that the PMR is likely full. From my understanding, LVM doesn't balance the data out. It will fill up a drive and then move on to the next. If you add another, it will fill up the 2nd drive and then start on the newly added drive. Maybe it does do some magic but does the OS know which drive data is going to hit? It seems to me that we could end up stuck with SMR or pay a premium for PMR. That's the part that worries me. I'm not saying SMR isn't good for a lot of folks but for us power type users, it matters. You get into servers and it matters a whole lot I'd imagine. Maybe I need to buy some drives before I can't even get them at a affordable price at all??? Dale :-) :-) P. S. Thanks to Michael for the info. I'll read it in a bit. Having a little sewer problem. Dirty job. -_o
