On Thu, Dec 29, 2011 at 11:37 AM, Roman Mamedov <r...@romanrm.ru> wrote: > On Thu, 29 Dec 2011 11:21:14 +0700 > "Fajar A. Nugraha" <l...@fajar.net> wrote: > >> I'm trying fstrim and my disk is now pegged at write IOPS. Just >> wondering if maybe a "btrfs fi balance" would be more useful, since:
> Modern controllers (like the SandForce you mentioned) do their own wear > leveling 'under the hood', i.e. the same user-visible sectors DO NOT > neccessarily map to the same locations on the flash at all times; and > introducing 'manual' wear leveling by additional rewriting is not a good > idea, it's just going to wear it out more. I know that modern controllers have their own wear leveling, but AFAIK they basically: (1) have reserved a certain size for wear leveling purposes (2) when a write request comes, they basically use new sectors from the pool, and put the "old" sectors to the pool (doing garbage collection like trim/rewrite in the process) (3) they can't re-use sectors that are currently being used and not rewritten (e.g. sectors used by OS files) If (3) is still valid, then the only way to reuse the sectors is by forcing a rewrite (e.g. using "btrfs fi defrag"). So the question is, is (3) still valid? -- Fajar -- 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
