RetroFedFormat a 512e drive to 4096 on Linux
printf("%s", name);https://piefed.blahaj.zone/c/techsupport@lemmy.world/p/880794/format-a-512e-drive-to-4096-on-linux
Edit: feedback
Thanks for all the advice! Hereās some funny feedback: it was a faulty drive š¤£ give me back my feelings š obviously Iām sending it back
I have just received my Seagate 18TB IronWolf Pro HDD and the specs say that the logical sector size is 512 emulated. Moreover, Seagate says that switching to 4096 sector size is as easy as doing a quick format (Windows terminology?). I suppose on Linux this simply means creating a filesystem with that block size? For instance mkfs.ext4 -b 4096 /dev/device or - in my specific case - cryptsetup luksFormat --sector-size=4096 and then creating a file system?
What confuses me is the Arch Wiki article on advanced format that has instructions on how to use hdparm to tell the firmware to use a certain sector size.
Do I need to do the hdparm thing, which seemingly conflicts with the Seagate instructions?
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Use sg_format to run a low level format on the disk. 512E vs 4kN isnāt going to change much in a homelab environment. If you create a filesystem with 4k clusters, Linux will send 4k wrudte blocks to the disk. The firmware on the disk will write that out into 8 logical disk sectors, usually in a single 4k physical sector. I use my storage mainly for media and thereās no performance difference between my 512E disks and my 4nN disks. I simply donāt have an intense and sensitive enough environment to show the performance gain. Iād say leave the low level formating alone and just write a filesystem on top of it with 4k blocks.
What do you mean?
Low level formating is how the data tracks are layed out on the disk platters, itās what the drive firmware sees. hdparm and sg_format instruct the disk to rearrange those tracks. High-level formatting is what the OS sees when you run mkfs. It creates a new file system or replaces an existing one.
And how is the low level format related to subject? (If it is really possible to trigger it by some tool.)
OP was asking how to switch between 512 byte sectors and 4096 byte sectors. A low level format is how to do that. Itās triggered by the sg_format tool on Linux, or by a tool provided by the drive manufacturer.
His drive is 512e, it is not switchable.
Erasing the partition table and/or uefi metadata space.
Totally unrelated, but I just want to say that my 14 TB sas drive (exos?) was brought back to life in a 12 TB configuration after failure by using openseachest to deactivate one side of one of the platters (the failing one, it was the only one with errors) after I told it to start it took 4 days to reformat, most of that time reporting no progress, but finally finished and now it works great!
TL;DR: Everything should work well with default settings, no special actions required.
First of all, partitions must be aligned to sector size (multiples of 4096). Most partitioning tools align partitions to 1MiB by default nowadays, so this shouldnāt be a problem, however if the disk is already partitioned, check the partition offset. For ext4, as well as most modern filesystems, default block size is 4KiB, so you donāt need to pass optional parameters to
mkfs. Forcryptsetup luksFormatthere are also two things that must be set correctly:--align-payload(2048 512-byte sectors by default, equal to 256 4096-byte sectors, no need to change), and--sector-size(for 512e device it should be set to 4096 bytes automatically, no need to set manually).Sweet! I feel this kind of āprovesā Seagateās stance, in other words, that a quick format will suffice, since most tools these days defualt to 4096 byte sectors. Although one has to read between the lines a bitā¦
Thanks for your help!
Except for leaving things default, almost none of that comment is true.
4k is default for most disks today. Some transition-era ssds used 8k blocks.
Do not worry about emulated block size, because ssds only use that to report to the filesystem, no sectors exist on solid state media.
Although this post is about an HDD š«£
Edit: but if I can leave things at default and not touch
hdparmeither REGARDLESS, Iām happy š¤£Well SSDs have flash pages, which are essentially sectors as they are the smallest unit you can read/write, and theyāre usually 4096 bytes on NAND flash. My understanding is to write to a flash page you have to erase the whole block of 32+ pages before writing, so if a 512e SSD doesnāt receive the rest of the page in time (e.g. with IO scheduling, 512 byte fs sectors, unaligned partitions, or bad luck), then the controller has to do a read-erase-program across the whole block of pages (although wear leveling will probably read + copy the modified page to elsewhere instead), instead of just a single program operation on one page (assuming a properly trimmed SSD).
So IMO, 4Kn is more important on SSDs, yet every vendor sets 512e by default. Luckily quite a few NVMe SSDs (not Samsung), let you change the logical block size with an nvme format command.
But more related to the OP, HDDs are a lot slower and donāt have to erase multiple sectors before a write, so itās not as important, however partition alignment is still important but usually handled automatically in every modern partitioning tool. Sometimes you can switch a HDD to 4Kn with
hdparm, but this isnāt common, and youāve said your HDD is dead anyway, so it wonāt help.Also, sorry about bringing you into this, I have strong opinions against 512e SSDs haha.
I think weāre talking past each other here: You are talking about blocks as physical delineations in an ssd, containing many pages with erase cycles. Op is talking about the filesystem view of blocks, which is different altogether. ZFS, for instance, should have its block size aligned with what a disk presents to the HAL, or you end up with lots of wasted space or terrible performance.
For SSDs (youāre right, outside opās problem), the internal block size is usually much bigger than the emulated block size, often 128K. But we donāt use filesystems with 128K block sizes, or we couldnāt reasonable run databases or store small files.
There was a brief time in the wild west of SSDs being new where some shipped with 8k blocks, but this caused a bunch of problems for storage drivers because no one had yet decided if the translation of FS blocks to should be handled by filesystems or by disk firmware. We now let manufacturers decide how they should r/w to media, and trust the firmwareās presented block size.
That block size is now 4k for most disks, spinning or ssd. We still see some weird layouts in high-performance or high-endurance disks, but they are exceptions.
Iām not sure what this means, pages are a concept in an ssdās physical structure, they donāt mean anything to a filesystem (except in volatile memory).
Iām pretty sure OP is confused themselves, but I read this as referring to the physical sector size.
Fair enough, I probably explained it poorly. The problem is that pages donāt mean anything to the filesystem, but the way the filesystem is layed out means a lot to the pages. With 512e, the SSD has to buffer each write until it can make up the whole 4K page. Itāll also buffer a read until the whole 4K page is read. So if those buffers never become full/read, such as when the filesystem isnāt aligned to itās pages, or the read/writes arenāt in the right sequence, then it destroys your performance.
This also happens with HDDs, but theyāre slow enough to be able to rearrange operations, though an unaligned filesystem will still cause unnecessary reads before writes.
feedback
Thanks for all the advice! Hereās some funny feedback: it was a faulty drive š¤£ give me back my feelings š obviously Iām sending it back
No Fast Format is needed on a modern linux system with a modern filesystem. Outside of very specific tuned workloads, it wonāt make any noticable difference as linux already is detecting and optimizing for the 4k physical sectors.