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awarded  Nice Answer
Jan
9
answered What is PKG_PATH for linux?
Dec
23
comment authentication in linux
You cannot sign in to any unix system without using at least a username, at least not if you want this for "a particular user".
Dec
17
answered File systems vs partitions vs directories
Dec
16
comment Netctl causes getty to clear the screen and re-display the issue message
What distro are you using? Which are the services that configure your network? Is it possible, that the change in network configuration triggers a restart of services that allow logon?
Dec
14
awarded  Popular Question
Dec
10
comment Creating a sparse (automatically expanding and contracting) swap file with hole-punching support
No, if you had 20GB swap all together, the kernel would know about it and never use 21GB. If the kernel knows there are 100GB available swap space, there are no reasons to do anything else than use the 21st GB after the first 20GB. I do not know the error handling when the kernel is unable to use the swap space it thinks it has. If it is robust enough to handle this, I'd say using swap files over partitions and overcommitment of swapspace is the way to go for virtualization hosts.
Dec
10
comment Creating a sparse (automatically expanding and contracting) swap file with hole-punching support
I mean that if you use a 100GB SSD for this experiment and your kernel thinks there are 100GB of swap space available, but in reality there are only 20GB available, because other data has been put on the disk in the meantime, then you will be in trouble if the kernel attempts to swap out 21GB. Conversely, if you will never put any other files on the 100GB SSD then it is totally unnecessary to make the swap file sparse, because it can always access the full 100GB.
Dec
10
comment Creating a sparse (automatically expanding and contracting) swap file with hole-punching support
For B, you will be fine using a SSD, otherwise it is a very well understood problem, that the number of heads in a disk is finite and small. For D, if you are not going to use the disk for anything else than swap, why even bother making the swap space sparse?
Dec
10
comment Creating a sparse (automatically expanding and contracting) swap file with hole-punching support
For A I think you have to create the filesystem on the disk accordingly. If you introduce a loopback mounted fs into the procedure, the buffering that occurs can become problematic. If swapping occurs and a big chunck of swap space is requested a big chunk of disk space is requested which, in the case of a loopback mount, will result in a fairly large amount of memory being allocated, exacerbating the original memory shortage. I have no idea how much fine tuning of the kernel is possible to prevent this.
Dec
10
comment Creating a sparse (automatically expanding and contracting) swap file with hole-punching support
D) However, if you promise the system more swap space than your disk can deliver, I would expect nothing less than an unrecoverable system freeze in case the kernel actually wants to use a single bit more swap space than there is available on your disk.
Dec
10
comment Creating a sparse (automatically expanding and contracting) swap file with hole-punching support
A) The first problem I can think of is, that if the blocksize of the fs the swapfile lives in is smaller than the memory page size(s), there may be a swapped out memory page with a lot of zeros, which will result in fallocate punching holes. If this page is to be swapped in latter what happens then? B) I believe fragmentation will become an issue pretty quickly with such an approach. C) Apart from that, I'd trust in the kernels abstraction layers that this is a valid approach.
Dec
10
comment How to delete Ubuntu without damaing another Linux distro?
It can be this easy, but it needn't be. That's why I asked many questions (the list is not exhaustive) to motivate you to tell us more about your set up. We cannot know which OS you put on which partition. You will have to find out. The command mount will be very helpful for this task. You have to boot into one of your Linuxes, mount all three partitions (one should be mounted as / already) and find out which partition shelters which OS. Then you need to find out which boot loader you are using, where it is installed and how it is configured, because we cannot tell.
Dec
8
answered How can Wireshark see packets dropped by iptables?
Dec
8
reviewed Approve Is it possible to transfer a file from a Linux Bash script to Windows without mounting the server folder?
Dec
8
reviewed No Action Needed Bash to clear historic content folders
Dec
8
reviewed Reviewed DNS Master vs Slave and Primary vs Secondary
Dec
8
comment How to recognize binaries installed in `~/bin`?
This looks like a duplicate of unix.stackexchange.com/q/170156/19575 At least the problem is the same.
Dec
8
reviewed Edit and Reopen combine selected column multi file
Dec
8
revised combine selected column multi file
I spelled it out for them as it seems the OP has bigger problems with the english language.