What SMART Stats Tell Us About Hard Drives
backblaze.com
What SMART Stats Tell Us About Hard Drives
1–10 of 71 posts
Re: What SMART Stats Tell Us About Hard Drives
#2SMART is a fantastic exercise in sensitivity and specificity. As backblaze is showing with this data, SMART stats have poor sensitivity, but what's much worse for those who run big fleets of drives is their poor specificity. Lots of healthy drives are reported unhealthy by SMART. If I'm running a gold-plated database server, that doesn't matter. A couple of extra planned drive replacements is a small price to pay for avoiding unplanned failures. If I'm running a huge drive cluster, it's much, much more expensive.
Take Backblaze's 0.01% for a group of four failures. That's replacing an extra 100 drives per million, at random, and only getting the benefit of correctly predicting failures 10.4% of the time.
This is great data to have.
Re: What SMART Stats Tell Us About Hard Drives
#3SMART is a fantastic exercise in sensitivity and specificity. As backblaze is showing with this data, SMART stats have poor sensitivity, but what's much worse for those who run big fleets of drives is their poor specificity. Lots of healthy drives are reported unhealthy by SMART. If I'm running a gold-plated database server, that doesn't matter. A couple of extra planned drive replacements is a small price to pay for…
Nice analysis.
Re: What SMART Stats Tell Us About Hard Drives
#4This is good info to know, helps me as a sysadmin to be confident in making decisions for my customers and their data. I regularly use a tool called Crystaldiskinfo to check the SMART stats of drives. Will pay more attention to the raw values in the future.
Re: What SMART Stats Tell Us About Hard Drives
#5Wow. They provide all of the raw log data from the drives[0]. Looks like an interesting source of data for a Kaggle competition.
Re: What SMART Stats Tell Us About Hard Drives
#6Interesting, thanks for posting! Could you talk quickly about why it's interesting to predict drive failure? Is it to understand how many replacement drives you might need to order in the short term, or is there value beyond stock management of drives?
Re: What SMART Stats Tell Us About Hard Drives
#7This data should be put into smartmontools or a separate tool to give a simple good/bad rating as the actual values are somewhat meaningless w/o data.
Re: What SMART Stats Tell Us About Hard Drives
#8SMART is a fantastic exercise in sensitivity and specificity. As backblaze is showing with this data, SMART stats have poor sensitivity, but what's much worse for those who run big fleets of drives is their poor specificity. Lots of healthy drives are reported unhealthy by SMART. If I'm running a gold-plated database server, that doesn't matter. A couple of extra planned drive replacements is a small price to pay for…
Thresholds are often useful with these kinds of stats. Aka a drive moving one sector might mean nothing, but moving 30 in a week could be great predictor. Further they only have 70k drives across a range of product lines so what predicts drive X failing very well might say little about drive Y.
PS: Rememebr all RAM gets bit flit errors over time. Which is one of the reasons rebooting is often so useful, but also means one off errors are often meaningless.
Re: What SMART Stats Tell Us About Hard Drives
#9Interesting, thanks for posting! Could you talk quickly about why it's interesting to predict drive failure? Is it to understand how many replacement drives you might need to order in the short term, or is there value beyond stock management of drives?
Not OP, but:
Perfect predictability would obviously be beneficial, in that you could get by without any redundancy. But even imperfect predicability can help you reduce the required number of drives for a set level of security.
Re: What SMART Stats Tell Us About Hard Drives
#10SMART is a fantastic exercise in sensitivity and specificity. As backblaze is showing with this data, SMART stats have poor sensitivity, but what's much worse for those who run big fleets of drives is their poor specificity. Lots of healthy drives are reported unhealthy by SMART. If I'm running a gold-plated database server, that doesn't matter. A couple of extra planned drive replacements is a small price to pay for…
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