Friends who are new to NAS may think that NAS is a bit expensive, but NAS veterans know: to play NAS, hard disk is the biggest investment. This NAS hard drive primer will help novices get started quickly with NAS hard drives and save at least 2 pitfalls.
Although NAS is a bit expensive, it is really not difficult to buy, because there are fewer pitfalls in hardware equipment, no matter new or old machines, as long as the price is right, you can start. Hard disks are much harder to buy, new hard disks are expensive, and second-hand hard disk pits. Especially the pit of the second-hand hard disk is so deep that old birds often overturn. So the first advice for newbies is: don't buy second-hand mechanical hard drives at the entry stage.
Western Digital distinguishes hard drives by color is deeply popular, and for the convenience of writing, this article uses Western Digital as an example. Seagate and Toshiba have the same type of products. Mechanical hard disks are divided into many kinds according to different performance, including home blue disks, purple disks for monitoring, red disks for NAS, enterprise-level black disks, and large-capacity helium disks. NAS does not have to use professional NAS hard drives, if the read and write intensity is not large, blue and purple disks can also do the job. In particular, the purple disk has low power consumption, is cheaper, and supports 7x24-hour operation, which is a substandard for the red disk.
As a novice with a small budget, you can start with purple disks, and you can also buy red disks and black disks with a large budget, but NAS players basically buy enterprise disks later. Because the enterprise disk capacity is large, the performance is more stable, and the cost performance is not bad. Large-capacity enterprise disks are generally recommended to buy 12-18T cost-effective, NAS old players will go to the sea to find a few new enterprise hard disks when the e-commerce promotion or the exchange rate is good (this year's exchange rate has dropped a little, I don't know how cost-effective this year's overseas amoy is). However, unless you have the budget to buy it all at once, I don't recommend starting directly with a high-capacity hard drive. Because hard disks need to consider data migration and backup in addition to large capacity, it is not enough to rely on one hard disk to do all the data.
Large-capacity machinery above 4T still has a price advantage over solid-state (mechanical price is about 100 yuan / T), and mechanical hard disks are more suitable for cold backup, so the main storage of NAS players is mechanical hard disks. But the price of mechanical hard drives is now rotten, which makes everyone a little uncomfortable. Solid-state prices fell sharply, but machinery prices rose instead of falling. The reason is very simple: 1. Large-capacity mechanical hard disk still has advantages over solid-state prices; 2. Mechanical hard disk has entered a bottleneck period, there is no room for cost decline, market share is still decreasing, it is better to increase prices to increase profits.
Since new hard disks are expensive, many NAS users choose to jump the pit of second-hand hard disks, how deep is this pit? I'll talk about it:
Four kinds of second-hand hard disks are not recommended to buy: 1. Refurbished disks of bad disks; 2. Zero out old disks and replace them with new labels; 3. Zero out old disks; 4. Hard disks with bad sectors. But the problem is that almost all home-grade mechanical hard disks can be perfectly zeroed (there are relatively few new disks cleared during the sales period), not only that, but also household mechanical hard disks can be renovated in various ways: changing labels, changing circuit boards, and even dismantling and repairing are not too difficult. This makes it difficult to judge the actual use time and real health of a second-hand mechanical hard disk. Unless you can confirm that this mechanical hard drive is an old drive that individual users have first-hand, you will never guess what the story of this hard drive has gone through.
Like my credo is not to buy refurbished and zeroed plates, but has been in the pit a few times. The second-hand purple disk I bought in the second-hand market twice before all overturned: once it was the old Hitachi zero disk to replace the purple disk labeling, S.M.A.R.T could not see the clue, but the hard disk operating temperature was as high as 60 °C, which was 20 °C higher than the normal hard disk of the same device; Once was to buy an old purple disk in 2017, it may be that the merchant changed S.M.A.R.T technology to be too rusty, resulting in CrytalDiskInfo being unable to read the hard disk S.M.A.R.T and thus showing the stuffing.
The refurbishment of the enterprise disc is slightly better, because the helium disc can only do the appearance renovation and zeroing, and it is difficult to do the opening refurbishment. Moreover, it is generally difficult to clear new enterprise-level disks:
| Western Digital: HC320 is perfectly cleared, HC330, HC530 can be cleared, HC550 is generally said on the Internet that it cannot be cleared temporarily |
| Seagate: x16, x18 perfect zeroing, x20 It is generally said on the Internet that it cannot be cleared for the time being |
| Toshiba: MG07 perfect zeroing, MG08, MG09 imperfect zeroing, MG10 generally said on the Internet that it cannot be cleared for the time being |
Whether the household disk or the enterprise disk can be cleared is not absolute, and the firmware may be cleared after a long time if it is leaked or cracked. Therefore, the most important thing to buy a used hard drive is the channel, reputation, and the experience of S.M.A.R.T and disk scanning to judge the use of the hard disk.
It's not that you can't buy a second-hand hard drive, but it's a bit difficult to encounter a suitable used hard drive, and it takes experience to identify it. For example, I bought 4 4T blue disks some time ago: the appearance is a new disk after 2021 (small probability of renovation), the power-on time is 10,000 hours (the probability of clearing is small), and the 4 power-on time is exactly the same, in line with the seller's hard disk cabinet self-use hard disk, this is the personal use hard disk. But now the probability of encountering this situation is too small, and the self-use hard disk at the right price is basically swept by the traffickers. That's why I don't recommend newbies to buy used hard drives.
There is also a small tip: novices do not toss RAID first. Home NAS is soft RAID, CPU overhead and multiple hard disk reads and writes increase power consumption (increased power consumption, increased hard disk wear, RAID does not play a role in data protection for novices). And today's off-the-shelf NAS can back up critical files without RAID. Newbies don't toss RAID and there's no problem at all.
To summarize briefly: novices can start with 4-8T air disks, choose monitoring disks, household disks, and enterprise disks according to actual purchasing power, and the subsequent data storage will upgrade 10-18T enterprise disks. Do not touch used hard drives until you are familiar with the hard drive model, appearance characteristics, and know how to analyze S.M.A.R.T (unless the seller is absolutely reliable). At present, the price of mechanical hard disk is basically disk, the price of the new disk is about 100 yuan / T floating, if it is significantly lower than this price, then it is necessary to investigate whether the purchase channel is reliable. With this cost concept, you can build the right hard disk warehouse for your NAS.
Second-hand mechanical hard disk is not recommended to be shipped for more than 5 years, and enterprise-level is not recommended to be shipped for more than 7 years. It's not that it can't be used, but the S.M.A.R.T information for such drives is completely unreliable. For example: the blue disk in 2018, the result of the power-on time is only 2000 hours, do you think this hard disk has been cleared to zero? The story of these hard drives is already difficult to verify. If it is not cleared, these old disks show more than 30,000 hours of power-on, which means that for blue disks and purple disks, the spare sector may be running out, and the failure rate has begun to rise. It's not impossible that you insist on missing this kind of second-hand disk, this is such a second-hand disk will not be much cheaper, I just don't think there is any need to greed for this small bargain to put the data at risk.
That's it for now!