Robert Nichols wrote: > On 05/22/2010 08:40 PM, Les Mikesell wrote: >> Robert Nichols wrote: >>> On 05/22/2010 07:39 PM, Robert Nichols wrote: >>> I should add that the kernel normally will do I/O in multiples of its 4KB >>> (typical) page size where possible, but I have no idea whether any effort >>> is made to align those writes if the drive does not report a 4KB physical >>> sector size, or whether it even makes sense to try beyond what the >>> elevator algorithm does for coalescing sequential writes. >>> >>> I don't currently have any of these "enhanced format" drives, nor am I >>> using RAID, so all I can report is the collected experience of others. >> Well, the form factor is certainly nice. I got a hot-swap carrier with 2 slots >> that fits in a floppy bay and the drives themselves are tiny so it seemed ideal >> for copies of data to go offsite. I just wish it would work... Even a dd at >> the disk level seems slow so I'm not sure the writes are being aggregated even >> if you ignore partitioning and offsets. > > Another thing to keep in mind is that the SATA spec. only requires the > internal SATA connector to withstand 50 insertions. I picked up some > nice acomdata (TM) eSATA housings for the drives (512-byte sectors, > thankfully) I use for my offsite backup copies. The eSATA connector > is spec-ed for 50,000 insertions. My laptop came with a warning about > the life of that connector, and I found those ratings mentioned at > http://www.serialata.org/technology/esata.asp . 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. -- Les Mikesell lesmikesell at gmail.com