What is the largest file transfer you have ever done?
I'm writing a program that wraps around dd to try and warn you if you are doing anything stupid. I have thus been giving the man page a good read. While doing this, I noticed that dd supported all the way up to Quettabytes, a unit orders of magnitude larger than all the data on the entire internet.
This has caused me to wonder what the largest storage operation you guys have done. I've taken a couple images of hard drives that were a single terabyte large, but I was wondering if the sysadmins among you have had to do something with e.g a giant RAID 10 array.
Not that big by today's standards, but I once downloaded the Windows 98 beta CD from a friend over dialup, 33.6k at best. Took about a week as I recall.
I remember downloading the scene on American Pie where Shannon Elizabeth strips naked over our 33.6 link and it took like an hour, at an amazing resolution of like 240p for a two minute clip 😂
In similar fashion, downloaded dude where's my car, over dialup, using at the time the latest tech method - a file download system that would split the file into 2mb chunks and download them in order.
No wonder. That file is super slow to transfer for some reason. but wait till you get to /dev/urandom. That file hat TBs to transfer at whatever pipe you can throw at it...
/dev/random and other "files" in /dev are not really files, they are interfaces which van be used to interact with virtual or hardware devices. /dev/random spits out cryptographically secure random data. Another example is /dev/zero, which spits out only zero bytes.
Both are infinite.
Not all "files" in /dev are infinite, for example hard drives can (depending on which technology they use) be accessed under /dev/sda /dev/sdb and so on.
In grad school I worked with MRI data (hence the username). I had to upload ~500GB to our supercomputing cluster. Somewhere around 100,000 MRI images, and wrote 20 or so different machine learning algorithms to process them. All said and done, I ended up with about 2.5TB on the supercomputer. About 500MB ended up being useful and made it into my thesis.
A small dcp is around 500gb. But that's like basic film shizz, 2d, 5.1 audio. For comparison, the 3D deadpool 2 teaser was 10gb.
Aspera's commonly used for transmission due to the way it multiplexes. It's the same protocolling behind Netflix and other streamers, although we don't have to worry about preloading chunks.
My laughter is mostly because we're transmitting to a couple thousand clients at once, so even with a small dcp thats around a PB dropped without blinking
Entire drive/array backups will probably be by far the largest file transfer anyone ever does. The biggest I've done was a measly 20TB over the internet which took forever.
Outside of that the largest "file" I've copied was just over 1TB which was a SQL file backup for our main databases at work.
From an order of magnitude perspective, the max is terabytes. No "normal" users are dealing with petabytes. And if you are dealing with petabytes, you're not using some random poster's program from reddit.
I’ve done a 1PB sync between a pair of 8-node SAN clusters as one was being physically moved since it’d be faster to seed the data and start a delta sync rather than try to do it all over a 10Gb pipe. M
It was something around 40 TB X2 . We were doing a terrain analysis of the entire Earth. Every morning for 25 days I would install two fresh drives in the cluster doing the data crunching and migrate the filled drives to our file server rack.
The drives were about 80% full and our primary server was mirrored to two other 50 drive servers. At the end of the month the two servers were then shipped to customer locations.
In the middle of something 200tb for my Plex server going from a 12 bay system to a 36 LFF system. But I've also literally driven servers across the desert because it was faster than trying to move data from one datacenter to another.
Just thinking about how much data you could transfer using this. MicroSD cards makes it a decent amount. Latency would be horrible, but throughput could be pretty good I think.
From LA to Vegas. Took the servers down end of business one night, drove it all night, installed it and got it back online before start of business the next day.
I’ve migrated petabytes from one GPFS file system to another. More than once, in fact. I’ve also migrated about 600TB of data from D3 tape format to 9940.
I once abused an SMTP relay (my own) by emailing Novell a 400+ MB memory dump. Their FTP site kept timing out.
After all that, and them swearing they had to have it, the OS team said "Nope, we're not going to look at it". Guess how I feel about Novell after that?
I don't remember how many files, but typically these geophysical recordings clock in at 10-30 GB. What I do remember, though, was the total transfer size: 4TB. It was kind of like a bunch of .segd, and they were stored in this server cluster that was mounted in a shipping container for easy transport and lifting onboard survey ships. Some geophysics processors needed it on the other side of the world. There were nobody physically heading in the same direction as the transfer, so we figured it would just be easier to rsync it over 4G. It took a little over a week to transfer.
Normally when we have transfers of a substantial size going far, we ship it on LTO. For short distance transfers we usually run a fiber, and I have no idea how big the largest transfer job has been that way. Must be in the hundreds of TB. The entire cluster is 1.2PB, bit I can't recall ever having to transfer everything in one go, as the receiving end usually has a lot less space.
I worked at a niche factory some 20 years ago. We had a tape robot with 8 tapes at some 200GB each. It'd do a full backup of everyone's home directories and mailboxes every week, and incremental backups nightly.
We'd keep the weekly backups on-site in a safe. Once a month I'd do a run to another plant one town over with a full backup.
I guess at most we'd need five tapes. If they still use it, and with modern tapes, it should scale nicely. Today's LTO-tapes are 18TB. Driving five tapes half an hour would give a nice bandwidth of 50GB/s. The bottleneck would be the write speed to tape at 400MB/s.
A few years back I worked at a home. They organised the whole data structure but needed to move to another Providor. I and my colleagues moved roughly just about 15.4 TB. I don't know how long it took because honestly we didn't have much to do when the data was moving so we just used the downtime for some nerd time. Nerd time in the sense that we just started gaming and doing a mini LAN party with our Raspberry and banana pi's.
Surprisingly the data contained information of lots of long dead people which is quiet scary because it wasn't being deleted.
No idea about which specific type of business it is, but keeping that history long term can have some benefits, especially to outside people. Some government agencies require companies to keep records for a certain number of years. It could also help out in legal investigations many years in the future and show any auditors you keep good records. From a historical perspective, it can be matched to census, birth, and death certificates. A lot of generational history gets lost.
Companies also just hoard data. Never know what will be useful later. shrug
@data1701d downloading forza horizon 5 on Steam with around 120gb is the largest web-download, I can remember. In LAN, I’ve migrated my old FreeBSD NAS to my new one, which was a roughly 35TB transfer over NFS.
Back in the late 90’s I worked for an internet search company, long before Google was a thing. We would regularly physically drive a dozen SCSI drives from a RAID array between two datacenters about 20 miles apart.
~15TB over the internet via 30Mbps uplink without any special considerations. Syncthing handled any and all network and power interruptions. I did a few power cable pulls myself.
I’ve got symmetrical gigabit in my apartment, with the option to upgrade to 5 or 8. I’d have to upgrade my equipment to use those speeds, but it’s nice to know I have the option.
Yeah, I also moved from 30Mb upload to 700Mb recently and it's just insane. It's also insane thinking I had a symmetric gigabit connection in Eastern Europe in the 2000s for fairly cheap. It was Ethernet though, not fiber. Patch cables and switches all the way to the central office. 🫠
Most people in Canada today have 50Mb upload at the most expensive connection tiers - on DOCSIS 3.x. Only over the last few years fiber began becoming more common but it's still fairly uncommon as it's the most expensive connection tier if at all available.
How long did that take? A month or two? I've backfilled my NAS with about 40 TB before over a 1 gig fiber pipe in about a week or so of 24/7 downloading.
I downloaded that 200gb leak from national public data the other day, maybe not the biggest total but certainly the largest single text file ive ever messed with
I think 16 terabytes? Might have been twelve. I was consolidating a bunch of old drives and data into a nas for a friend. He just didn't have the time, between working and school and brought me all the hardware and said "go" lol.
Upgraded a NAS for the office. It was reaching capacity, so we replaced it. Transfer was maybe 30 TB. Just used rsync. That local transfer was relatively fast. What took longer was for the NAS to replicate itself with its mirror located in a DC on the other side of the country.
Yeah it's kind of wild how fast (and stable) rsync is, especially when you grew up with the extremely temperamental Windows copying thing, which I've seen fuck up a 50mb transfer before.
The biggest one I've done in one shot with rsync was only about 1tb, but I was braced for it to take half a day and cause all sorts of trouble. But no, it just sent it across perfectly first time, way faster than I was expecting.
Never dealt with windows. rsync just makes sense. I especially like that its idempotent, so I can just run it twice or three times and it'll be near instant on the subsequent run.
My Chia crypto farm at its peak had about 1.5 PB of plots, each plot was I think about 100ish gigs? I'd plot them on a dedicated machine and then move them to storage for farming. I think I'd move around 10TB per night.
It was done with a combination of powershell and bash scripts on Windows, Linux, and the built in Windows Services for Linux.
Largest one I ever did was around 4.something TB. New off-site backup server at a friends place. Took me 4 months due to data limits and an upload speed that maxed out at 3MB/s.
When I was moving from a Windows NAS (God, fuck windows and its permissions management) on an old laptop to a Linux NAS I had to copy about 10TB from some drives to some other drives so I could re-format the drives as a Linux friendly format, then copy the data back to the original drives.
I was also doing all of this via terminal, so I had to learn how to copy in the background, then write a script to check and display the progress every few seconds. I'm shocked I didn't loose any data to be completely honest. Doing shit like that makes me marvel at modern GUIs.
Took about 3 days in copying files alone. When combined with all the other NAS setup stuff, ended up taking me about a week just in waiting for stuff to happen.
I cannot reiterate enough how fucking difficult it was to set up the Windows NAS vs the Ubuntu Server NAS. I had constant issues with permissions on the Windows NAS. I've had about 1 issue in 4 months on the Linux NAS, and it was much more easily solved.
The reason the laptop wasn't a Linux NAS is due to my existing Plex server instance. It's always been on Windows and I haven't yet had a chance to try to migrate it to Linux. Some day I'll get around to it, but if it ain't broke... Now the laptop is just a dedicated Plex server and serves files from the NAS instead of local. It has much better hardware than my NAS, otherwise the NAS would be the Plex server.
When I was in highschool we toured the local EPA office. They had the most data I've ever seen accessible in person. Im going to guess how much.
It was a dome with a robot arm that spun around and grabbed tapes. It was 2000 so I'm guessing 100gb per tape. But my memory on the shape of the tapes isn't good.
Looks like tapes were four inches tall. Let's found up to six inches for housing and easier math. The dome was taller than me. Let's go with 14 shelves.
Let's guess a six foot shelf diameter. So, like 20 feet circumference. Tapes were maybe .8 inches a pop. With space between for robot fingers and stuff, let's guess 240 tapes per shelf.
That comes out to about 300 terabytes. Oh. That isn't that much these days. I mean, it's a lot. But these days you could easily get that in spinning disks. No robot arm seek time. But with modern hardware it'd be 60 petabytes.
I'm not sure how you'd transfer it these days. A truck, presumably. But you'd probably want to transfer a copy rather than disassemble it. That sounds slow too.
Multiple TB when setting up a new server to mirror an existing one. (Did an initial copy with both together in the same room, before moving the clone to a physically separate location. Doing that initial copy would saturate the network connection for a week or more otherwise)
I synced to the BSV shitcoin which is 11+ terabytes. So large I had to turn on throwing away the rest of what I downloaded because it wouldn't fit on all of the storage media I own. I feel sorry for the people running an archive node.
Manually transferred about 7TBs to my new Rpi4 powered NAS. It took a couple of days because I was lazy and transferred 15 GBs at a time which slowed down the speed for some reason. It could handle small sub 1 GB files in half a minute otherwise.
Could the slowdown be down to HDDs that cache on a section of - I think it's single layer? - and slowly rewrite that cache onto the denser (compound layer?) storage?
I routinely do 1-4TB images of SSDs before making major changes to the disk. Run fstrim on all partitions and pipe dd output through zstd before writing to disk and they shrink to actually used size or a bit smaller. Largest ever backup was probably ~20T cloned from one array to another over 40/56GbE, the deltas after that were tiny by comparison.
Today I've migrated my data from my old zfs pool to a new bigger one, the rsync of 13.5TiB took roughly 18 hours. It's slow spinning disks storage so that's fine.
The second and third runs of the same rsync took like 5 seconds, blazing fast.
As the Anaconda installer of Fedora Atomic is broken (yes, ironic) I have one system originally meant for tweaking as my "zygote" and just clone, resize, balance and rebase that for new systems.
Remote? 10GB MicroWin 11 LTSC IOT ISO, the least garbage that OS can get.
Why would dd have a limit on the amount of data it can copy, afaik dd doesn't check not does anything fancy, if it can copy one bit it can copy infinite.
Even if it did any sort of validation, if it can do anything larger than RAM it needs to be able to do it in chunks.
No, it can't copy infinite bits, because it has to store the current address somewhere. If they implement unbounded integers for this, they are still limited by your RAM, as that number can't infinitely grow without infinite memory.
Not looking at the man page, but I expect you can limit it if you want and the parser for the parameter knows about these names. If it were me it'd be one parser for byte size values and it'd work for chunk size and limit and sync interval and whatever else dd does.
Also probably limited by the size of the number tracking. I think dd reports the number of bytes copied at the end even in unlimited mode.
Well they do nickname it disk destroyer, so if it was unlimited and someone messed it up, it could delete the entire simulation that we live in. So its for our own good really.
~340GB, more than a million small files (~10KB or less each one). It took like one week to move because the files were stored in a hard drive and it was struggling to read that many files.
My cousin once stuffed an ISO through my mail server in '98. His connection up in Bella Bella restricted non-batched comms back then, so he jammed it through the server as email to get on the batched quota.
It took the data and passed it along without error, albeit with some constipation!
Probably ~15TB through file-level syncing tools (rsync or similar; I forget exactly what I used), just copying my internal RAID array to an external HDD. I've done this a few times, either for backup purposes or to prepare to reformat my array. I originally used ZFS on the array, but converted it to something with built-in kernel support a while back because it got troublesome when switching distros. Might switch it to bcachefs at some point.
With dd specifically, maybe 1TB? I've used it to temporarily back up my boot drive on occasion, on the assumption that restoring my entire system that way would be simpler in case whatever I was planning blew up in my face. Fortunately never needed to restore it that way.
I can't imagine how nerve-wracking it would be to run dd on something like that lol. I still don't trust myself to copy a USB stick with my unimportant bullshit on it with dd, let alone a server with anything important on it!