On 05/24/2010 12:41 PM, Les Mikesell wrote: > On 5/24/2010 6:56 AM, Robert Nichols wrote: >> >>> >>> The trayless internal hotswap enclosures claim to be good for 10,000+ insertions >>> and I'm using larger ones for the desktop drives I had been using without any >>> problems. I have seen some postings to the effect that I need a newer kernel >>> to recognize the 4k sectors besides doing the partition alignment. Maybe I can >>> boot the RHEL 6 beta or a fedora iso and see if they are faster. >> >> Sounds good, unless that 10,000 insertion spec is predicated on spreading >> the usage among 200 drives such that no individual drives has more than >> 50 insertions. ;-( >> >> BTW, I got carried away typing zeros in that spec. for the eSATA connector. >> The right number is 5,000 insertions, not 50,000. >> >> If you want a good write-up on what the kernel developers have to contend >> with to handle these 4KiB sector sizes, see >> https://ata.wiki.kernel.org/index.php/ATA_4_KiB_sector_issues >> >> For those with a strong stomach for such things, a nice historical >> perspective on the horrors of ever-increasing drive sizes can be found >> at http://www.win.tue.nl/~aeb/linux/Large-Disk.html . Just be sure to >> keep the 2004 date in mind when it mentions "recent kernels." > > I booted a RHEL6 beta DVD in rescue mode, but it wasn't any better. > That version of fdisk does show: > Logical/Physical Sector size 512 bytes > though, so it's probably hopeless. Oddly, that version of fdisk > wouldn't let me move the beginning back below 63 either - but I did that > with the 5.x fdisk. The only other thing I can think of to try would be to use 'dd' with a blocksize that is a multiple of 4K directly into a raw partition located at each of the 8 possible alignments and see if any of them gives better throughput. I suppose it's possible that something in the USB bridge chip (guessing that the enclosure presents a USB interface) won't allow the 4K write to pass. Any chance of experimenting with one of those drives hooked directly to an SATA port? -- Bob Nichols "NOSPAM" is really part of my email address. Do NOT delete it.