There's an odd behavior people have encountered with Crucial MX500 drives.
Sometimes, or under the triggering conditions, SMART's "pending sectors" (0xC5 / 197) goes up gradually, then down quickly (like, a minute).
There's no increase in "reallocation event count" (0xC4).
In another forum someone suggested "the problem could be the cable", but that makes no sense, as the pending sector count is a completely internal state.
Anyone reached any conclusions on what causes the following, and any practical implications?
Here's the pending sector count over a span of some 2 hours, reading the same 50GB area 3 times, with some idle time after each cycle.
The pending sector count goes up from 0, up to 51 while reading, then down quickly during idle. Then, more read/idle rounds. (The time axis isn't linear.)
The drive I tested was only lightly used, and spent most of its time unpowered.
The files I read during testing were written more than 6 months prior, maybe even a year.
Main drive stats:
500 GB, half empty (but probably not actively TRIMmed because of a USB enclosure)
150 powered hours
1.4 TB written
6 average block-erases (0xAD)
1.65 WAF (1 + 0xF8 / 0xF7)
M3CR043 firmware
I'm theorizing, maybe it's related to flash cell charges that dissipating while unpowered, which leads to sectors requiring more error correction. Then, during idle, the drive rechecks or rewrites.
If the theory is correct, an open question is why do pending sectors still collect after the first test round. Though the peak is lower each time.
FWIW, 0xF8 "Background program page count" did increase while doing the reads, but I think less so in later rounds (didn't check carefully).
It also continued increasing slowly during idle time.
Sometimes, or under the triggering conditions, SMART's "pending sectors" (0xC5 / 197) goes up gradually, then down quickly (like, a minute).
There's no increase in "reallocation event count" (0xC4).
In another forum someone suggested "the problem could be the cable", but that makes no sense, as the pending sector count is a completely internal state.
Anyone reached any conclusions on what causes the following, and any practical implications?
Here's the pending sector count over a span of some 2 hours, reading the same 50GB area 3 times, with some idle time after each cycle.
The pending sector count goes up from 0, up to 51 while reading, then down quickly during idle. Then, more read/idle rounds. (The time axis isn't linear.)
The drive I tested was only lightly used, and spent most of its time unpowered.
The files I read during testing were written more than 6 months prior, maybe even a year.
Main drive stats:
500 GB, half empty (but probably not actively TRIMmed because of a USB enclosure)
150 powered hours
1.4 TB written
6 average block-erases (0xAD)
1.65 WAF (1 + 0xF8 / 0xF7)
M3CR043 firmware
I'm theorizing, maybe it's related to flash cell charges that dissipating while unpowered, which leads to sectors requiring more error correction. Then, during idle, the drive rechecks or rewrites.
If the theory is correct, an open question is why do pending sectors still collect after the first test round. Though the peak is lower each time.
FWIW, 0xF8 "Background program page count" did increase while doing the reads, but I think less so in later rounds (didn't check carefully).
It also continued increasing slowly during idle time.
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- we don't actually know what it's measuring.
