What are the warning signs when a NAS hard drive is broken? My red plate lasted five years before dying; I missed the first three of the five signals

my Western Digital red disk WD30EFRX at home has been running in NAS for five years and two months, powered for 24,000 hours, and got off last autumn. Looking back at the post-review log, it actually started messaging me since spring—strange noises, slow speed, worsening sleep performance. I kept treating it as 'the old system is like this' and pushed it through until a health alert popped up in the background. This article explains the signals I missed and how to read SMART numbers. If your home plate shows any of the following signs, don't follow my example.

clarify first: the mechanical disc was damaged by dragging, not sudden death

many people still think of a bad hard drive as "it was fine yesterday and suddenly can't recognize it today." Mechanical discs can indeed be this dead—the magnetic head hitting the disc or the motor freezing, leaving instantly, but this is purely like a lottery. The vast majority of disks die by dragging: a certain point on the disc surface magnetically attenuates, requiring repeated retries to read and write there—this is the beginning of bad circuits; Then, the perimeter of this point gets bigger and larger, retries become more frequent, and one day the head in this area really can't read, so the firmware moves the data directly to the spare sector and marks this area as unusable—this action is called remapping. From the budding to the spread of bad paths to 'remapping can't save them,' it's usually measured in months, with the window period being the time you have to escape.

my red plate is exactly this rhythm. The first click was in March, the file copy started freezing in June, the SMART alert at the end of September, and the short-term test failed in mid-October. Looking back, I spent nearly half a year of buffer time just hoping for luck.

five signals, I missed the first three

sorted in order of appearance, the first three are the easiest to overlook:

Signal 1: Occasional clicking sounds. isn't the usual sizzling sound of a hard drive's read/write routine, but rather a muffled 'click-click' sound with a few seconds of intervals. The official call this is the sensor's abnormal noise when it returns to position. It's best to recognize it late at night and listen right next to the case. Once or twice isn't a big deal; as the frequency increases, you need to be alert. When I heard it in March, I thought it was case resonance, so I just picked up a book to cover it and got it done.

Signal 2: Transmission speed is abruptly jittered. copying large files, which was stable at 180MB/s, suddenly dropped to a few MB/s or even reset to zero, then resumed after a few seconds, the whole process felt like an ECG. This is a direct manifestation of the magnetic head repeatedly retrying in the bad sector area. Note that slow transmission network is stable, while gigabit means it can't reach 110MB/s but won't reset to zero; The bad path is unpredictable speed, slow down. The first time I encountered it in June, I even restarted the switch, completely in the wrong direction.

Signal 3: Sleep is getting harder and harder. When there are bad sectors on drive, the system's backend inspections and retries will increase, showing that the originally tuned hard drive is sleeping suddenly sleeping restlessly. When my home failed to hibernate, I checked Docker and searched containers all night, but found nothing. Actually, by then SMART's pending sector had already gone from 0 to 4.

Signal 4: Backend Health Alert. Feiniu's storage management and Synology's storage manager will pop up notifications when SMART is abnormal, and Synology will also send emails. At this point, it means the system has read the numbers for you once. Just don't click them off—this is an open card.

Signal 5: Slow or drop-off on cold start. after restarting the NAS, it takes over ten seconds to recognize this drive; sometimes you might as well just fail to recognize it and then restart it. At this point, it's the countdown—I encountered it a week after receiving the alert.

truly solid evidence: SSH to check the SMART Five Tests

ears and sensations are just clues; the numbers are the evidence. Feiniu runs SSH and Synology do the same, running this route:

smartctl -a /dev/sda

dozens of items, don't panic—only five are truly worth watching. I'll rank them by importance:

two common pitfalls to talk about. First, the raw_value column is the original value. Some drives use hexadecimal storage. Don't be scared when you see 1000—after some conversion, it might be 16. Second, UDMA_CRC this item has wronged many good sellers—it counts cable transmission errors. If you plug in a SATA cable or replace a cable, the number won't go up again. Don't buy just because it doesn't look like zero.

just looking at the numbers isn't enough, you can proactively run a short test, and get results in two or three minutes:

smartctl -t short /dev/sda

finished, use smartctl -a to check the result paragraph. PASS means the current readable is active, FAIL basically prepares for the future. My drive crashed within a week after a short test failed, and my sense of bad sectors was sharper than a human ear.

What to do if

finds a problem: back up first, then decide whether to replace it

order must never be reversed. I've seen too many people do the opposite—first deciding which new property to switch to, then waiting for delivery to finish the order for a few days. Stories like this happen every year on Tieba. The correct order is:

first step, back up immediately. don't care about anything, just copy the things on this drive that can't be re-downloaded the backup copy them elsewhere. During the bad sector spread period, every full drive scan is a death sentence. When copying, pick the most important ones first; don't start grinding slowly from the first folder. The last thing I copied out before dying on that drive were family photos and documents. I had over 300GB of Blu-ray original discs stored in stock and gave up on them — I just downloaded those things again.

the second step, evaluate whether to replace it. Pending Zero or short-term test failure, no negotiation, switch. Reallocated is only in single digits and hasn't increased for months. Temperature and sound are normal, so you can keep observing, but the inspection frequency has been increased to once a month. For older disks (over 50,000 hours of power), even if the numbers are clean, it's recommended to include them in your replacement plan. Don't wait for them to age along with another part in RAID.

Step three: Swap the deck. RAID units are directly put into new developments for reconstruction. Be careful not to swap two units at once. The tens of hours during reconstruction are the period when the remaining old properties face the greatest pressure. For details, see the reconstruction timeline in my article on how to choose RAIDs for details. Single-drive setups without RAID are simpler: new drives are upgraded, data is copied back, and old drives are retired. You can check the inventory and capacity ledger when buying new units I calculated the two and four units , don't buy smaller ones again.

to revitalize for a long time, do three things well in daily life

afterwards, I reviewed the facts and found that my red plate wasn't badly served, but there are three things I could do better, and I want to remind everyone:

cooling. mechanical disc lifespan is most sensitive to temperature; discs that consistently run above 45 degrees Celsius will fail early. Later, I added a case fan to lower the disk temperature to around 38 degrees, costing 20 yuan. Stacking trays stacked together is the easiest for heat accumulation, so you can stack one compartment at a time.

scanning and re-operation moved early in the morning. doing a full panel inspection or SMART long-term test—which lets the head run a full circuit—during the lowest-occupying hours in the early morning, it's the same approach as I moved tasks to the early morning hours to save electricity costs—not to disrupt daytime use, but to keep the disk routine regular.

don't start and stop too often, and don't be afraid of starts. a tossing disk that starts and stops more than ten times a day, or a work disk that never shuts down for seven years, are not advisable. Just set a reasonable sleep cycle according to your usage rhythm. Also, I pay attention to power quality. My home experiences frequent power outages, so I later got a UPS installed. Unstable voltage is a hidden killer for the hard drive.

To wrap it up

be fair: the mechanical wheel is actually quite sturdy—it lasts 24,000 hours before dying, and before it dies, it gives a six-month warning—more reliable than many people think. The real unreliability is human luck-based mentality. Spend two minutes running SmartCTL once a month, store digital screenshots to compare trends, and not miss any of these five signals. Data is priceless, but disks have value. Once you understand this order, the NAS situation is secure.