If your computer's hard drive isn't enough, can you mount a NAS on your own chassis? After a night of iSCSI messing around, three pitfalls were scarier than expected

the desktop in the study, the 512GB SSD finally became popular, with only about thirty GB left. Even editing and exporting videos was nerve-wracking. The most annoying thing is the material management software I use. The material library only recognizes local drive paths, and when I enter NAS shared folders , it ignores me. Adding a 2TB SATA SSD costs 600 to 700 yuan. I suddenly remembered there's another way—to attach the NAS space to a "local hard drive" on the computer, iSCSI. After a night of fussing around, I managed to get through it, but there were three pitfalls I wanted to give people a heads-up.

SMB and iSCSI differ by a translator

first break down these two terms. When we connect to a NAS, we use SMB: you open \192.168.31.20\ Library on your computer, see folders and files, copy them in and drag them out. Throughout this process, the NAS acts as a translator—it translates the files on its hard drive into network protocols and hands them to you, clearly knowing the name, size, and layer of each file.

iSCSI is a different logic: the NAS carves out a space from the storage pool, doesn't install a file system, and hands it directly to the computer; The computer received was a "brand new hard drive," which was partitioned and formatted as NTFS itself. For example, in SMB, when you borrow something from the warehouse, every item you pick up must be registered by the administrator; iSCSI means the administrator directly moves an entire empty shelf into your home. The administrator has no idea what to put on it or how to arrange it, nor does it want to know.

this 'not knowing' is exactly what I want—for a computer, it's like a local drive, with drive letters, partitionable partitions, and a D:\ path. Software that only recognizes local drives immediately accepts. The cost also comes from this 'not knowing' part; you'll see this later when we talk about the pitfall.

NAS this: How do you turn on Feiniu and Synology

My N100 small machine runs Feiniu, but it never had this feature before. After the system updated to 0.9.3x last month, iSCSI quietly appeared in the settings. The path is to find iSCSI in the application, then create a new LUN using advanced "LUN Management"—you can think of it as creating a hard drive out of thin air on the NAS, choosing which storage pool it is in, and how much capacity it is. I marked 1 T in the material library.

there's an option here called Thin, which is worth mentioning: check it, and filling in 1 T is just the upper limit; the actual amount is counted. I only copied 180GB into the NAS storage pool that night, so the storage pool on the NAS side was just 180GB short. If you don't check it, it's a thick stockpile and you lose 1 T on the spot, which isn't friendly for old NAS with limited space. Also, which storage pool a LUN is placed in is important. ext4 Btrfs article discussed the temperament of two file systems. If you want to take a snapshot of a LUN, the pool must be Btrfs.

LUN build the Target, it's like opening a door for this bare disk. The house number is a string of characters called IQN, no need to write it yourself, just generate it by default. Step three is permissions: Feiniu checks which initiators to connect in the "User Group" section. The logic on Synology's side is the same, except the entry point is changed to the SAN Manager in the package center. After installation, you create iSCSI LUNs and Targets, with the process being largely similar. My cousin owns a second-hand Synology car I casually drove one, and it only takes five minutes.

the computer: Windows comes with built-in tools, four steps to complete

Now it's the computer's turn. Windows comes with iSCSI to start programs, so you don't need to install anything. Win+R iscsicpl press Enter. The first pop-up asks if you want to start the iSCSI service. Click yes. Then switch to the "Discover" tab, click the Discovery portal, enter the NAS IP, and keep port 3260 unchanged; Go back to the 'Target' tab. The Target you just created is already in the list. Select and click to connect.

at this point, the disk still can't be seen, don't panic. Then Win+R type diskmgmt.msc to open Disk Management, and a "Unknown, Uninitialized" disk appears—right-click the left disk tab, first click "Online," then click "Initialize Disk," and select GPT as partition type; Then right-click on the right side of the unallocated space, create a new simple volume, then proceed to the next step, select NTFS as the file system, and assign it a drive letter. Once confirmed, the computer will have a 1TB D drive. The whole process is exactly like plugging in a brand-new hard drive into a computer.

By the way, the order of disconnection should be reversed: first set that disk to "offline" in Disk Management, then return to iSCSI to initiate the program and disconnect. What happens if you unplug the network cable directly (shut down and restart the NAS)? I've stepped on it, let's look below.

test: Sequential read/write maxes out at gigabits, randomness is a weak point

I have expectations for speed, and actual tests basically match. Copy large files into this "local drive," write stability at 106MB/s; Backread is 108MB/s—my home is a gigabit network, and the switch to the network card is wired throughout. This number is maxed out for gigabit usage, on par with local SATA solid-state sequential read/write speed. want to go faster, you have to the network. 2.5G ports can reach 280 or 90 yuan, but that's another matter.

shortcoming lies in random read/write. Each time a data block is addressed, it runs back and forth on the local area network. Although it's only a fraction of a millisecond, high-frequency operations like 4K small files amplify this amount. The feel is obvious: drag a video into the software and then quickly drag the progress bar. Scrub's response is a bit slower than the local SSD, roughly the feel of a local mechanical drive. Scenarios like the "write once, sequential read" scenario of the asset library are more than sufficient; If you want to use it as a system drive or a game board for competitive gaming, give up early.

has a rule written only for their own people: this thing is only for playing on the local area network. Some forums use it to use it as a public remote NAS device, causing latency to tens of milliseconds, iSCSI timeouts and a "drive drop." On computers, the drive letters disappear and software freezing, similar to the hard drive being powered out.

three pits, each more hidden than the last

pit one, and one LUN only allows one computer to connect. After I explained, my cousin's first reaction was, "So if this drive is attached to two computers at home, isn't that basically sharing?" — please stop there. NTFS is not a cluster file system; two machines write to the same disk simultaneously, and the file system's ledger records separately and overwrites each other. At best, the file gets corrupted; at worst, the entire disk is scrapped. Even chkdsk may not be able to save everything. Feiniu's user group permissions and the list of allowed program initiators in Synology's Target—frankly, they're all helping you guard this line. If multiple machines really want to share files, SMB obediently leave, that's what you're doing.

pitfall two: on the NAS side, you can't see what you put in. You stuff this "D drive" fully into your computer, and when you check the file manager on the NAS, you'll find only a large file with a name containing LUN; If you delete 100GB from your computer, the NAS storage pool space remains completely unchanged—the simplified configuration account only counts the actual block written to the file system, while NTFS deleting files only changes the directory and does not notify the underlying layer. Over time, this can lead to a confusing record. the troubleshooting approach from the article on Where did the storage pool space go? It also applies here. What's worse is that one day you accidentally delete this LUN on the NAS management interface, the entire "drive" evaporates instantly, and the Recycle Bin can't save it. accidental deletion rescue method basically powerless against the internal data of the LUN—the NAS only deletes one large file, and the 100,000 files inside have never existed for it.

pitfall three: the few minutes after NAS restart are a minefield. On the first night, after setting up a NAS, I immediately restarted: the NAS I set scheduled to restart at 4 a.m. restarted by itself, and I still had a few tasks left to write on the drive. As soon as the NAS disconnects, the drive on the computer disappears instantly, the file I was writing to is instantly corrupted, and a chkdsk pops up on startup. Later, I set rules for both sides: NAS reboot times should avoid my working hours, and if the computer isn't used for long periods, I'd take the drive off first. You need to be even more cautious about power outages. The UPS at home is now protected by both the NAS and optical modem router, so don't let this "local drive" experience a hard power outage.

who is worth trouble with, and who should you ignore

If you just dislike the computer drive and don't want to open the case, there's actually a much easier way: plug a USB external hard drive into the NAS as a storage drive , plug and play without running the system. The path of iSCSI is reserved for those cornered by software that "only recognizes local drives"—like me.

Here's the order to wrap up: Create LUN on the NAS, check Simplify Configuration — Create Target, lock permissions — Computer connects to iscsipl portal — Disk management and online initialization and formatting — First try reading and writing small files, then relocate the master — Remember to take the computer offline when not in use. After completing these six steps, your C-drive with the red light alarm can finally catch its breath.