On April 18, 2018 8:35:41 AM CDT, [email protected] wrote: >> I guess that would mean that scattering unused space on an SSD >between the partions, means the controller probably sees it as being >used. I left chunks allocated at the ends of the drives as recommended. >I was just wondering if my stripes would increase that wear level >capability, as well as providing for emergency recovery space(s). > >Trying to guess how a drive does its wear leveling is impossible. >Even if you are buying SSDs directly from the manufacturer and have a >relationship with them, they usually won't tell you how it works. > >Usually the drive has some extra space by design that it can use as a >pool for writes, and then the old blocks are erased and put into the >pool. >If you use trim, you can add currently unused space in the filesystem >to >that free pool too. Some drives will occationally move data that never >changes from blocks that have very few writes to blocks that are more >work >in the hopes that it will then be able to use those better blocks for >more >frequently changing data, but simpler drives may not do such >housekeeping. >There really isn't any way to know, unless they choose to advertise it. >Of course it is likely a drive with a much higher promised number of >write cycles likely is doing smarter housekeeping to keep block wear as >even as possible. > >I am not currently convinced that keeping unallocated space is worth >it. >Sure you make the free pool a bit larger, but you still end up writing >the same amount of blocks and you make the usable size smaller. Having >a >larger free pool might help for systems that do a lot of writes since >you are more likely to be able to have a free block to do a write, >while the drive hasn't had time to erase the old blocks. On the other >hand if you are doing enough writing that it could be a proble, maybe >and SSD is the wrong type of drive to be using. > >I have all my SSDs fully allocated and see no reason to do otherwise. >Some people have some crazy theories that often have no facts behind >them. >They just assume the drive makers are dumb and haven't thought of this >amazing problem that they just thought of. Of course some of the >really >cheap drives really are that dumb.
Thats what I tell people about my Phone. Its a smart phone. It just has a dumb operator. :-) I've always left bits of HDDs unalocated for emergency recovery installs. Live distros on usb make that provision unnecesary. Hugh also posted an interesting link to a page, I think it was on blkdiscard for thinly provisioned SSD's. Haven't gone there yet, but soon will. Thanks for your followup. > >-- >Len Sorensen -- Russell --- Talk Mailing List [email protected] https://gtalug.org/mailman/listinfo/talk
