Yeb Havinga wrote:
So for the Intels it's probably also lifetime writes in GB but you'd
have to check with an Intel smart values reader to be absolutely sure.
With my 320 series drive, the LBA units are pretty clearly 32MB each.
Watch this:
root@toy:/ssd/data# smartctl --version
smartctl 5.40 2010-07-12 r3124 [x86_64-unknown-linux-gnu] (local build)
...
root@toy:/ssd/data# du -skh pg_xlog/
4.2G pg_xlog/
root@toy:/ssd/data# smartctl -a /dev/sdg1 | grep LBAs
241 Total_LBAs_Written 0x0032 100 100 000 Old_age
Always - 18128
242 Total_LBAs_Read 0x0032 100 100 000 Old_age
Always - 10375
root@toy:/ssd/data# cat pg_xlog/* > /dev/null
root@toy:/ssd/data# smartctl -a /dev/sdg1 | grep LBAs
241 Total_LBAs_Written 0x0032 100 100 000 Old_age
Always - 18128
242 Total_LBAs_Read 0x0032 100 100 000 Old_age
Always - 10508
That's an increase of 133 after reading 4.2GB of data, which means makes
each LBA turn out to be 32MB in size. Let's try to confirm that by
doing a write:
root@toy:/ssd/gsmith# smartctl -a /dev/sdg1 | grep LBAs
241 Total_LBAs_Written 0x0032 100 100 000 Old_age
Always - 18159
242 Total_LBAs_Read 0x0032 100 100 000 Old_age
Always - 10508
root@toy:/ssd/gsmith# dd if=/dev/zero of=test_file.0 bs=32M count=25 && sync
25+0 records in
25+0 records out
838860800 bytes (839 MB) copied, 5.95257 s, 141 MB/s
root@toy:/ssd/gsmith# smartctl -a /dev/sdg1 | grep LBAs
241 Total_LBAs_Written 0x0032 100 100 000 Old_age
Always - 18184
242 Total_LBAs_Read 0x0032 100 100 000 Old_age
Always - 10508
18184 - 18159 = 25; exactly the count I used in 32MB blocks.
--
Greg Smith 2ndQuadrant US greg@xxxxxxxxxxxxxxx Baltimore, MD
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