Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hi, > I believe that this is no problem at all, as it writes only zeros (if the > source disc is "really" empty). Unfortunately, in our product, I cannot assume that the source disk is "filled with zeroes" in those parts of the disk that is "free". > Why I come to this conclusion? On SSD discs without trim support and no trim > utility from the vendor, it's a well known technique to use SecureErase and > write zeros all over the disc, to restore factory default > settings/performance for such discs. (and this works!) Thanks for this info, I was not 100 % sure this worked fine. However setting a disk to factory default by writing zeroes to the entire disk requires taking that disk out of service ofcourse. This is also a problem in the product I work with. So the options are limited. There are specific situations in our products life-cycle where this is possible to do, and there we already do it. So maybe I can use this a "fallback remedy" to recover SSD perfromance. br Håkan > From: christoph at iway.ch > To: drbd-user at lists.linbit.com > Date: Tue, 15 Nov 2011 12:21:29 +0100 > Subject: [DRBD-user] Fw: DRBD SSD's and TRIM > > Hello Håkan > > >> secondary host/SSD. This is a bad thing to do with an SSD's since it > >> will conclude every block on the disk is occupied by "useful" data, and > >> it will have a large negative impact on the SSD's wear leveling > >> algorithm. Can somebody confim this conclusion ? > > Well, you can easily avoid the initial sync; as "unused" blocks will be > > returned as zeroes it won't cause "different" data on both sides. > > I believe that this is no problem at all, as it writes only zeros (if the > source disc is "really" empty). And any SSD should not taint the flash cells > if it sees that a complete erase block (I believe this is between 2MB and > 8MB on todays SSDs?) only consists of zeros. > > Why I come to this conclusion? On SSD discs without trim support and no trim > utility from the vendor, it's a well known technique to use SecureErase and > write zeros all over the disc, to restore factory default > settings/performance for such discs. (and this works!) > > regards > Christoph > > We're using SSDs in production systems for ~3 years now and had only > positive experiences so far. (we have way over hundred SSDs already deployed > in servers) > > _______________________________________________ > drbd-user mailing list > drbd-user at lists.linbit.com > http://lists.linbit.com/mailman/listinfo/drbd-user -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.linbit.com/pipermail/drbd-user/attachments/20111115/8674076c/attachment.htm>