Enhancement to power modes of modern HDDs #263
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I pushed some updates to:
I saw many discussion on high head load cycle count on different forums. Typical settings for smartd has setting of 0.5 hour polling cycle, which may lead to 224365*5=87600 head cycle for a 5-yr drive lifecycle. So this PR could be of help for those concerns raised by smartd. |
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This PR include 2x changes:
The 1st change trys to resolve issue in #138 and #141.
One problem with modern HDDs is the more aggressive idle_a timer. Some (Seagate Exos 7E10, X18, X20, etc) may need only 10ms to enter idle_a. In
smartmontools/smartmontools/smartd.cpp
Line 3576 in 65707ca
The fix #138 and #141 do not address the issue at its root since it just increase the timeout. What's more, 10-disc HDDs now need 25s to spin up which is longer than we expect in
smartmontools/smartmontools/smartd.cpp
Line 267 in 65707ca
The main purpose of 1st commit is to change condition of re-check power mode from
0 <= powermode(compare againstactive) todontcheck == 0(compare against -n condition). So even if a drive enters idle_a, it won't need re-check power mode and thus save 5s delay.The minor change in
scsiprint.cppin 1st change include some typo correction and correction forpowerlimit.powerlimitforLOW POWERshould be changed to lower power mode, becauseLOW POWERstands for an undivided power mode and lower power mode could avoid unnecessary spin up.The 2nd change is a rework for #126. Almost all modern HDDs enable idle_a and idle_b. But current
-nargument only acceptidleorstandby. The problem withidle_bis that HDD will unload its head assembly out of disk. So frequent idle_b switch will result in large load - unload count. That's why there are a lot of concerns on smart 193Load_Cycle_Countparameter. By divideidleorstandbyinto more detailed power modes, we could set-n idle_bto drive to limit increment of smart 193Load_Cycle_Count.Relative: WD whitepaper on power modes