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 .