Re: raid resync speed? - laptop drive-

[Robert Nichols <rnicholsNOSPAM@xxxxxxxxxxx>]

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 .

-- 
Bob Nichols     "NOSPAM" is really part of my email address.
                 Do NOT delete it.

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