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SUMMARY: Cannot copy more than 32GB of files to a 128GB memory stick formatted under FAT32 or exFAT despite the fact that I can format the stick and ChkDsk is showing the correct results after formatting (and also when less than 32GB of files are on the stick). I cannot use NTFS because this stick is designed to transfer files to an iPhone and the app will not handle NTFS. See below for details.
DETAILS:
I have a 128GB memory stick which is designed to quickly transfer files between a computer and an iPhone. One end is a USB and the other plugs into the iPhone's lightning port. This particular type is extremely common and looks like a "T" when you unfold it (Amazon link: https://www.amazon.com/gp/product/B07SB12JHG ).
While this stick is not especially fast when I copy Windows data to it, the transfer rate to my iPhone is much better than the wireless alternatives.
Normally I'd format a large memory stick or USB drive in NTFS, but the app used to transfer files to my iPhone ("CooDisk") will only handle exFAT and FAT32. I've tried both. For exFAT formatting, I've tried both Windows 7 and 10, and for FAT32 I used a free product from RidgeCrop consulting (I can give you the link if you want).
As with all USB storage devices, my stick is formatted as a single active partition.
I do not have a problem formatting. After formatting, ChkDsk seems happy with both FAT32 and exFAT. The CooDisk app works fine with either. After formatting, all the space is ostensibly available for files.
My problem arises when populating the stick with files.
Whenever I get beyond 32GB in total space, I have various problems. Either the copy will fail, or ChkDsk will fail. (After running ChkDsk in 'fix' mode, every file created beyond the 32GB limit will be clobbered.) Interestingly, when I use the DOS copy command with "/v" (verify) it will flag an error for files beyond the 32GB limit, although DOS XCopy with "/v" keeps on going. GUI methods also die at 32GB.
Out of sheer desperation, I wrote a script that uses GNU's cp for Windows. Now I can copy more than 32GB of files and ChkDsk flags no errors. However files beyond the 32GB limit end up being filled with binary zeros despite the fact that they appear as they should in a directory or Windows file explorer listing. (Weird, isn't it?)
I have also tried various allocation unit sizes from 4K all the way up to 64K and attempted this with three different Windows OSs (XP, Win7, and Win10).
Let me emphasize: there is no problem with the first 32GB of files copied to the stick regardless of: whether I use exFAT or FAT32; my method of copying; and my choice of AU size.
Finally, there is nothing in these directories that would bother a FAT32 or exFAT system: (a) file and directory names are short (well under 100 characters); (b) directory nesting is minimal (no more than 5 levels); (c) files are small (nothing close to a GB); and directories have relatively few files (nowhere close to 200, for those of you who recall the old FAT limit of 512 files per directory :)
The only platform I haven't yet tried is using an aging MacBook that someone gave to me. I'm not terribly good with Macs, but I would rather not be dependent on it (it's 13 years old, although MacBooks are built like tanks).
Also, is it possible that FAT32 and exFAT don't allow more than 32GB on an active partition (I can find no such limitation documented anywhere, in fact in my experience USB storage devices are always bootable - as was the original version of my stick)?
Any ideas??
As I have created a Debian VM inside VirtualBox by encrypting their partition. So that the OS must be running in an encrypted partition. Although while creating a disk image(VHD), I had given for Dynamic allocation, but after OS installation it looks the disk image was consuming the entire disk space. Now the image size is 20GB. Is it possible for us to compress or compact it to some smaller sizes. I saw the documentations to compact the disk image in Virtual Box, but I may need to know whether we can do the same for encrypted disk image.
Your help is greatly appreciated.
Thanks.
It depends on the type of encryption being used. Since you're using Debian I assume you're using LUKS, which is inflexible. The space has to be pre-allocated and therefore the image will utilise the full space allocated to it.
Yes, there is a way to do it, but too complex to do it.
Each time you need/want to compact it you need to do some steps carefully.
(Maybe this is not really need it, try first without this) Blank with zeros all free space inside 'clear' mounted partitions, so free space is zeroed in 'clear', it will not be zeroed in 'encrypted' view point, since encryption will encrypt such zeros.
Shutdown the machine and boot with a LiveCD iso that let you mount the virtual hdd you are using and a new 'dynamic' and 'empty' one.
Set the partition scheme and encription identically on the new one, but ensure encription will not do the 'fill' part, so it does not write all sectors... this is the top most important part... this way the new virtual disk is smalll in size, but encypted by you LUKs, etc.
At this point, only scheme and encryption is on the new 'small' one, now is time to mount both enctypted... the old and the new, so they can see in 'plain' at the same time.
Again this is very important, clone form the old 'plain' to the new 'plain' only sectors that have data (most tools to clone partitions does that).
As i say... the top most important thing (to get a smaller virtual HDD) is:
Create a new virtual dynamic disk empty
Partition it and Encrypt it without writting all sectors; so omit the dd with random data prior to do the encryption or else the dynamic file will grow to max), also omit the fill empty space, that again will grow the virtual disk to max
Clone the partitions from the plain view (mounted and de-crypted on fly), so the clone tool will only write data areas of files, etc, but not free space.
There is a small part that will not be able to be reduced... files inside encrypted partitions that have full clusters fill with zeros (hope you do not have any of thoose)... the cause is that such space (when no encryption, as is all zeros, the normal compat see the full cluster is zero so it does not need such space; but when it is encrypted, such cluster is not all zero inside the real virtaul disk file, so the compact method can not reduce it).
The idea behind all is:
When encryption is on... to get the smallest virtual disk size, start with a dynamic and empty one and write as less as possible clusters on it when cloning the previous one.
As said, it is too much work... and time to time, each write occurs it will start growing and growing again.
My best personal recomendation is, get a 'BIG' and 'FAST' disk and use a fixed virtual disk... if i read well and your disk is only 20GiB... you gain in speed a lot for having it fixed and not dynamic and will not get worried about 'fragmentation' etc.
Remember if you use a USB for it, get one able to write at 30MiB/s (if only have USB 2.0 ports), if you are lucky (like me) and have at least one USB 3 port (better if it is a USB 3.1 Gen 2 Type C) seach for a 2.5 inch HDD 500GiB Sata III (with write speed greater than 100MiB/s, it is really cheap, less than 25 euros) and a Sata III to USB 3.1 Gen 2 Type C enclosure (also cheap, some are under 15 euros)... and avoid having to 'reduce', 'clone' etc.
I have 10 virtual machines on a 500GiB (with more than 50% free space), each is 20GiB in size (with Windows system inside them taking near 16BiG) and VeraCrypt encryption... so i am on the quite near case to you... i opted to use a USB 3.1 gen 2 Type C enclosure to hold all the fixed size VDI files... my experience is that encrypted fixed size fly if compared to non encrypted dynamic size.
Of course, ensure you do the needed test (when encryption takes place), i mean... test virtual HDD speed with no encryption, then test encryption algorithms on ram... and choose a method that is faster than 1.6 times the speed of the disk... so encription will not be a bottle neck... else you can have a really bad speed caused by encryption.
Also think on this, how much cores you show to the guest? that will make encryption speed very different... but also think the worst case... how much CPU will use the non encryption threads on that guest?
Just as an example... if inside the guest you are doing LZMA2 compression (or video transcoding H.264 for example) etc... the free CPU for encryption is very low... so encryption will slow down things a lot... sample cases also do much I/O to disks, so encrypt/decrypt a lot per second is needed.
Maybe a better aproach... would be... encrypt the 'container' not the 'system'... in other words... encrypt where the VDI files are stored, not the whole guest system... create a container per VDI if want different phrase passwords, etc. That way the VDI can also be dynamic and be compacted, etc.
Of course, i would be of more help if you told what encryption scheme (without details) are using.
This makes a really great difference in possible answers:
Are you encrypting system partition with any tool that runs on guest? Then use the 'clone' only used clusters trick
Are you encrypting but setting the VDI encryption property on? Maybe VirtualBox console will help to compat them
Are you encrypting the container where VDI is stored? I am quite sure this is not your case, since in such case compact can be done as normal, VDI is not encrypted at all, neither anything iside it.
I talk about VDI... same applies to the rest formats, VHD, VHDx, etc.
Remember... if encription is done on guest and still want to reduce (compact) the virtua hdd file... start with a new dynamic one, put partition scheme, encryption but without filling all the disk... at this point virtual disk file size must not be great, just a few megabytes... then clone form the old to the new one all used clusters, but not the not used ones.
Advise: Prepare to repeat the 'compact' by 'cloning' a few times per 100 hours of intense use of the guest... if gain is less than 50% it does not compensate the effort... then the best can be done is use fixed size.
Special note: With Fixed size the access speed is much more than with dynamic size... having a dynamic size with 100% size as if it where fixed is a big lost in speed... how much? you must do the test in your machine, depends a lot on CPU, I/O speed (input/ouptup operations per second) of storage you have and also on transfer speed (MiB/s), and other factors... so best do some test.
Since you are talking about 20GiB... better do the test of fixed size... i am quite sure you will enjoy it a lot.
Other thing would be talking about 500GiB system partition with only 10% fill... since space gain could be 450GiB, it is wellcome to do the clone method to compact it, that is why i say how to do such... for such people and your you, and for any one.
P.D.: If someone does not know how to do something, that does not mean it is not possible, and if someone say something is not possible, better for that person explain the demostration or be prepeared to be called an idiot; technology improves a lot time to time, knowledge a lot more.
If a file is in a writing process, and at this time if I try to access it like if it is a log file which is being written every 10 milliseconds and I`m trying to access it will I damage or disturb the writing process?
Specifically I'm asking about video files, like if I start a recording process (using Windows Media Encoder) and at this time I would like to monitor the file if it is a blank file (black pixels everywhere) or there is a real content being recorded.
Sorry if my question is a newbie one, but I really really need to be sure about that.
Best on advance
In general you can certainly read files as they are being written, without corrupting their content. However:
It is possible to face an issue if your recording medium cannot deal with the combined data-rate or of both reading and writing. This can be a problem especially with slow-ish USB flash drives.
It is possible to face an issue on hard drives too, if the combination of reading and writing exceeds the rate of random seeks that the hard drive can handle. This can happen more easily on older drives (e.g. IDE) when dealing with HD video.
The end result is that if you have a real-time writer process, such as a TV recorder, it may be forced to drop some of the data - in the case of video a few frames.
Modern systems have quite fast disk subsystems, reasonably good I/O schedulers and large enough RAM capacities to allow for extensive data caching, which makes it quite unlikely that a single writer/reader combination would saturate the disk subsystem, unless you are doing something unusual like recording several video streams at once.
Keep in mind however, that:
The disk subsystem can also be saturated by unrelated processes reading/writing other files from the same drive.
If you are encoding video, you might also lose frames if something draws enough CPU resources that the encoding process is no longer able to keep-up with the real-time requirements. Depending on the video file, test-playing it might be just enough to do that - at least HD reproduction can be quite demanding. So, watch your CPU load and experiment before relying on it to record your favourite show :-)
EDIT:
If you are among the lucky ones that have SSD drives, seeks and data rate should normally be a non-issue. That leaves the CPU - you'd be surprised how easy it is to push it to the limit.
Above all, you should experiment to find out the limits of your system for each particular application. That way you won't have any nasty surprises...
I need to read and process a text file. My processing would be easier if I could use the File.ReadAllLines method but I'm not sure what is the maximum size of the file that could be read with this method without reading by chunks.
I understand that the file size depends on the computer memory. But are still there any recommendations for an average machine?
On a 32-bit operating system, you'll get at most a contiguous chunk of memory around 550 Megabytes, allowing loading a file of half that size. That goes down hill quickly after your program has been running for a while and the virtual memory address space gets fragmented. 100 Megabytes is about all you can hope for.
This is not an issue on a 64-bit operating system.
Since reading a text file one line at a time is just as fast as reading all lines, this should never be a real problem.
I've done stuff like this with 1-2GB before, albeit in Python. I do not think .NET would have a problem, though. But I would only do this for one-off processing.
If you are doing this on a regular basis, you might want to go through the file line by line.
Its bad design unless you know the files sizes vs the computer memory that would be avaiable in the running app.
A better solution would be consider memory mapped files. They use themselvses as page fil storage,
I've got a machine I'm going to be using for development, and it has two 7200 RPM 160 GB SATA HDs in it.
The information I've found on the net so far seems to be a bit conflicted about which things (OS, Swap files, Programs, Solution/Source code/Other data) I should be installing on how many partitions on which drives to get the most benefit from this situation.
Some people suggest having a separate partition for the OS and/or Swap, some don't bother. Some people say the programs should be on the same physical drive as the OS with the data on the other, some the other way around. Same with the Swap and the OS.
I'm going to be installing Vista 64 bit as my OS and regularly using Visual Studio 2008, VMWare Workstation, SQL Server management studio, etc (pretty standard dev tools).
So I'm asking you--how would you do it?
If the drives support RAID configurations in your BIOS, you should do one of the following:
RAID 1 (Mirror) - Since this is a dev machine this will give you the fault tolerance and peace of mind that your code is safe (and the environment since they are such a pain to put together). You get better performance on reads because it can read from both/either drive. You don't get any performance boost on writes though.
RAID 0 - No fault tolerance here, but this is the fastest configuration because you read and write off both drives. Great if you just want as fast as possible performance and you know your code is safe elsewhere (source control) anyway.
Don't worry about mutiple partitions or OS/Data configs because on a dev machine you sort of need it all anyway and you shouldn't be running heavy multi-user databases or anything anyway (like a server).
If your BIOS doesn't support RAID configurations, however, then you might consider doing the OS/Data split over the two drives just to balance out their use (but as you mentioned, keep the programs on the system drive because it will help with caching). Up to you where to put the swap file (OS will give you dump files, but the data drive is probably less utilized).
If they're both going through the same disk controller, there's not going to be much difference performance-wise no matter which way you do it; if you're going to be doing lots of VM's, I would split one drive for OS and swap / Programs and Data, then keep all the VM's on the other drive.
Having all the VM's on an independant drive would let you move that drive to another machine seamlessly if the host fails, or if you upgrade.
Mark one drive as being your warehouse, put all of your source code, data, assets, etc. on there and back it up regularly. You'll want this to be stable and easy to recover. You can even switch My Documents to live here if wanted.
The other drive should contain the OS, drivers, and all applications. This makes it easy and secure to wipe the drive and reinstall the OS every 18-24 months as you tend to have to do with Windows.
If you want to improve performance, some say put the swap on the warehouse drive. This will increase OS performance, but will decrease the life of the drive.
In reality it all depends on your goals. If you need more performance then you even out the activity level. If you need more security then you use RAID and mirror it. My mix provides for easy maintenance with a reasonable level of data security and minimal bit rot problems.
Your most active files will be the registry, page file, and running applications. If you're doing lots of data crunching then those files will be very active as well.
I would suggest if 160gb total capacity will cover your needs (plenty of space for OS, Applications and source code, just depends on what else you plan to put on it), then you should mirror the drives in a RAID 1 unless you will have a server that data is backed up to, an external hard drive, an online backup solution, or some other means of keeping a copy of data on more then one physical drive.
If you need to use all of the drive capacity, I would suggest using the first drive for OS and Applications and second drive for data. Purely for the fact of, if you change computers at some point, the OS on the first drive doesn't do you much good and most Applications would have to be reinstalled, but you could take the entire data drive with you.
As for dividing off the OS, a big downfall of this is not giving the partition enough space and eventually you may need to use partitioning software to steal some space from the other partition on the drive. It never seems to fail that you allocate a certain amount of space for the OS partition, right after install you have several gigs free space so you think you are fine, but as time goes by, things build up on that partition and you run out of space.
With that in mind, I still typically do use an OS partition as it is useful when reloading a system, you can format that partition blowing away the OS but keep the rest of your data. Ways to keep the space build up from happening too fast is change the location of your my documents folder, change environment variables for items such as temp and tmp. However, there are some things that just refuse to put their data anywhere besides on the system partition. I used to use 10gb, these days I go for 20gb.
Dividing your swap space can be useful for keeping drive fragmentation down when letting your swap file grow and shrink as needed. Again this is an issue though of guessing how much swap you need. This will depend a lot on the amount of memory you have and how much stuff you will be running at one time.
For the posters suggesting RAID - it's probably OK at 160GB, but I'd hesitate for anything larger. Soft errors in the drives reduce the overall reliability of the RAID. See these articles for the details:
http://alumnit.ca/~apenwarr/log/?m=200809#08
http://permabit.wordpress.com/2008/08/20/are-fibre-channel-and-scsi-drives-more-reliable/
You can't believe everything you read on the internet, but the reasoning makes sense to me.
Sorry I wasn't actually able to answer your question.
I usually run a box with two drives. One for the OS, swap, typical programs and applications, and one for VMs, "big" apps (e.g., Adobe CS suite, anything that hits the disk a lot on startup, basically).
But I also run a cheap fileserver (just an old machine with a coupla hundred gigs of disk space in RAID1), that I use to store anything related to my various projects. I find this is a much nicer solution than storing everything on my main dev box, doesn't cost much, gives me somewhere to run a webserver, my personal version control, etc.
Although I admit, it really isn't doing much I couldn't do on my machine. I find it's a nice solution as it helps prevent me from spreading stuff around my workstation's filesystem at random by forcing me to keep all my work in one place where it can be easily backed up, copied elsewhere, etc. I can leave it on all night without huge power bills (it uses <50W under load) so it can back itself up to a remote site with a little script, I can connect to it from outside via SSH (so I can always SCP anything I need).
But really the most important benefit is that I store nothing of any value on my workstation box (at least nothing that isn't also on the server). That means if it breaks, or if I want to use my laptop, etc. everything is always accessible.
I would put the OS and all the applications on the first disk (1 partition). Then, put the data from the SQL server (and any other overflow data) on the second disk (1 partition). This is how I'd set up a machine without any other details about what you're building. Also make sure you have a backup so you don't lose work. It might even be worth it to mirror the two drives (if you have RAID capability) so you don't lose any progress if/when one of them fails. Also, backup to an external disk daily. The RAID won't save you when you accidentally delete the wrong thing.
In general I'd try to split up things that are going to be doing a lot of I/O (such as if you have autosave on VS going off fairly frequently) Think of it as sort of I/O multithreading
I've observed significant speedups by putting my virtual machines on a separate disk. Whenever Windows is doing something stupid in the VM (e.g., indexing yet again), it doesn't thrash my Mac's disk quite so badly.
Another issue is that many tools (Visual Studio comes to mind) break in frustrating ways when bits of them are on the non-primary disk.
Use your second disk for big random things.