Gregg, Let me first say that TRIM is a somewhat "loose" standard, and even with the SATA 3.1 spec manufacturers are all over the map w/respect to how they've actually implemented it in their drives' firmware. Some aggressively erase and move data around on file updates, or use varying block sizes, command queuing etc, to implement wear leveling. Others take a simplistic approach and simply write new files to LRU areas.
The saving grace to TRIM is that you can always turn it off! If you sense your system is no faster (or even slower) with TRIM enabled, simply disable it. Both OS X and Windows enable TRIM by default on the SSDs that ship with their systems, so for general-purpose usage it seems there's some potential benefit to having it enabled. They're banking on the typical user usage of writing many small new files over time vs. constantly rewriting the same few large ones. I don't know what algorithm Crucial uses to implement TRIM. As I mentioned, we bought a bunch of Samsung SSDs and they seem to really fly with TRIM enabled (for our workload). It's really one of those YMMV situations. -Carl On Jan 15, 2014, at 11:11 AM, "Dinse, Gregg (NIH/NIEHS) [V]" <[email protected]> wrote: > Hi Carl, > > Thanks for the information about TRIM. I investigated a little and found a > few reports that said TRIM was a good thing, but also at least one that said > it might actually cause problems. > > One person said that TRIM is SATA-only and if an SSD is attached via PCIe (or > USB-3 or Firewire or Thunderbolt), then it cannot receive TRIM commands. > That person also said that enabling TRIM (on some SSDs) could increase wear > and tear by adding unnecessary writes. > > Clearly I am not highly technical in this area. My SSD (Crucial M4) is > mounted on a PCIe card that supposedly provides SATA-III access. So, if this > other person is correct, is my SSD considered to be SATA or PCIe? > > If you have other thoughts on this matter, I’d appreciate hearing them. In > your opinion, is there any risk of making things worse by enabling TRIM with > the Trim Enabler software? > > Thanks, > > Gregg > > On Jan 14, 2014, at 9:52 PM, Carl Hoefs <[email protected]> > wrote: > >> In a nutshell, TRIM spatially distributes writes across an SSD's memory so >> no particular spot of memory gets unduly utilized by writes and consequently >> "dies" or becomes slow due to soft (correctable) errors, which indicates the >> beginning of memory death. >> >> Apple enables TRIM for all of its own SSD drives. For 3rd-party drives, you >> have to do it yourself. There are free apps like Trim Enabler that are very >> easy to use. >> >> -Carl >> >> On Jan 14, 2014, at 7:43 PM, "Dinse, Gregg (NIH/NIEHS) [V]" >> <[email protected]> wrote: >> >>> Thanks for the suggestion, though I don’t know what TRIM is or which disk >>> utilization patterns would indicate that I should enable it. Can you >>> provide any details? >>> >>> Thanks, >>> >>> Gregg >>> >>> On Jan 14, 2014, at 9:37 PM, Carl Hoefs <[email protected]> >>> wrote: >>> >>>> On Jan 14, 2014, at 7:30 PM, "Dinse, Gregg (NIH/NIEHS) [V]" >>>> <[email protected]> wrote: >>>> >>>>> And although the system does not feel slower with the SSD than with my >>>>> old HDD, it also does not feel remarkably faster either, though I’m sure >>>>> some things are at least somewhat faster. >>>> >>>> Depending on your disk utilisation patterns, you might want to enable TRIM >>>> on the SSD. >>>> >>>> -Carl > _______________________________________________ MacOSX-talk mailing list [email protected] http://www.omnigroup.com/mailman/listinfo/macosx-talk
