From: Ivan L. Jr. <iva...@gm...> - 2013-11-29 15:13:48
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Hello, I was wondering if it is a good idea to have monitoring system call smartctl -A /dev/sdX somewhat frequently on my drives to monitor drives temperatures. I'm thinking 2-5 minutes interval, but I'm wondering how much of a performance hit on a drive is smartctl -A. In fact, I would love to monitor most of the values in in smartctl -A output, which could lead to about 17 calls each 5 minutes. I know this is a very dumb way to go about it, and some intermediary caching mechanism is perhaps a must, but still, how costly are these listings? Ivan |
From: Ivan L. Jr. <iva...@gm...> - 2013-12-07 13:03:12
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Can anyone answer this one too? :D On Nov 29, 2013, at 5:13 PM, Ivan Lezhnjov Jr. <iva...@gm...> wrote: > Hello, > > I was wondering if it is a good idea to have monitoring system call smartctl -A /dev/sdX somewhat frequently on my drives to monitor drives temperatures. I'm thinking 2-5 minutes interval, but I'm wondering how much of a performance hit on a drive is smartctl -A. > > In fact, I would love to monitor most of the values in in smartctl -A output, which could lead to about 17 calls each 5 minutes. I know this is a very dumb way to go about it, and some intermediary caching mechanism is perhaps a must, but still, how costly are these listings? > > Ivan |
From: Christian F. <Chr...@t-...> - 2013-12-07 15:14:20
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Ivan Lezhnjov Jr. wrote: > Hello, > > I was wondering if it is a good idea to have monitoring system call smartctl -A /dev/sdX somewhat frequently on my drives to monitor drives temperatures. I'm thinking 2-5 minutes interval, but I'm wondering how much of a performance hit on a drive is smartctl -A. This is drive firmware specific. The ATA SMART commands may or may not take significant time. For example ~0.1 to 0.3 seconds on older Samsung HDDs or older SandForce based SSDs. This could be tested with "smartctl -r ioctl ..." which also prints "Duration". |
From: John G. <gn...@to...> - 2013-12-08 01:18:36
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> > I was wondering if it is a good idea to have monitoring system call smartctl -A /dev/sdX somewhat frequently on my drives to monitor drives temperatures. I'm thinking 2-5 minutes interval, but I'm wondering how much of a performance hit on a drive is smartctl -A. It probably varies on each drive; measure it and decide for yourself if it's impacting your performance. > > In fact, I would love to monitor most of the values in in smartctl -A output, which could lead to about 17 calls each 5 minutes. I know this is a very dumb way to go about it, and some intermediary caching mechanism is perhaps a must, but still, how costly are these listings? Don't "cache" it. Call smartctl -A once and parse the listing once, to extract whatever 17 values you need. John |
From: Ivan L. Jr. <iva...@gm...> - 2013-12-13 07:43:40
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I've ran this command % time smartctl -r ioctl -A /dev/sda |egrep "durat|real" info=0x0 duration=0 milliseconds resid=0 info=0x0 duration=10 milliseconds resid=0 info=0x0 duration=13 milliseconds resid=0 info=0x0 duration=150 milliseconds resid=0 info=0x0 duration=23 milliseconds resid=0 real 0m0.236s user 0m0.033s sys 0m0.007s and there's apparently an extra overhead besides the ioctl commands, which is expected but it's pretty cool to see a breakdown like this :) This turns out to be a poor result on my system, though, as these numbers are two times less what they were initially on the first run: real 0m0.421s user 0m0.040s sys 0m0.010s Also, this data is for the older drive FUJITSU MHW2080BH. My brand new WDC WD20NMVW-11AV3S0 external USB drives scored real 0m0.067s user 0m0.050s sys 0m0.003s and real 0m0.040s user 0m0.033s sys 0m0.003s which is so much faster. Ivan On Dec 8, 2013, at 3:00 AM, John Gilmore <gn...@to...> wrote: >>> I was wondering if it is a good idea to have monitoring system call smartctl -A /dev/sdX somewhat frequently on my drives to monitor drives temperatures. I'm thinking 2-5 minutes interval, but I'm wondering how much of a performance hit on a drive is smartctl -A. > > It probably varies on each drive; measure it and decide for yourself if > it's impacting your performance. > >>> In fact, I would love to monitor most of the values in in smartctl -A output, which could lead to about 17 calls each 5 minutes. I know this is a very dumb way to go about it, and some intermediary caching mechanism is perhaps a must, but still, how costly are these listings? > > Don't "cache" it. Call smartctl -A once and parse the listing once, > to extract whatever 17 values you need. > > John > > |