>From what I have read, TRIM can also be done on demand for older systems or file systems that are not TRIM aware. For CentOS 5.x, a modified hdparm could be used to send the TRIM comamnd to the drive. Anyone have experience with this? -- Wade Hampton On Fri, Jul 19, 2013 at 1:05 PM, John R Pierce <pierce@xxxxxxxxxxxx> wrote: > On 7/19/2013 8:48 AM, Wade Hampton wrote: > > I found lots of references to TRIM, but it is not included > > with CentOS 5. However, I found that TRIM is in the > > newer hdparm which could be build from source, > > but AFIK is not included with CentOS 5 RPMS. That way, > > one could trim via a cron job? > > > trim is done at the file system kernel level. essentially, its a > extra command to the disk telling it this block is complete and the rest > of it 'doesn't matter' so the drive doesn't need to actually store it. > > > On 7/19/2013 7:10 AM, Alexander Arlt wrote: > > Hm. I'm not sure, if I'd go with that. In my understanding, I'd just buy > > something like a Samsung SSD 840 Pro (for not using TLC) and do a > > overprovisioning of about 60% of the capacity. With the 512GiB-Variant, > > I'd end up with 200GiB netto. By this way, I have no issues with TRIM or > > GC (there are always enough empty cells) and wear leveling is also a > > non-issue (at least right now...). > > those drives do NOT have 'supercaps' so they will lose any recently > written data on power failures. This WILL result in corrupted file > systems, much the same as using a RAID controller with write-back cache > that doesn't have a internal RAID battery. > > > > -- > john r pierce 37N 122W > somewhere on the middle of the left coast > > _______________________________________________ > CentOS mailing list > CentOS@xxxxxxxxxx > http://lists.centos.org/mailman/listinfo/centos > _______________________________________________ CentOS mailing list CentOS@xxxxxxxxxx http://lists.centos.org/mailman/listinfo/centos