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Avoid writing large amounts of data to system temp directory #996
Description
Reported by joseph07 in #haskell. stack setup failed due to not having enough space on the device, despite there being 38GB. According to pdxleif, archlinux defaults to using tmpfs, which stores it in ram, and so is limited in size.
Here's where a system temp directory is used as a place to unpack the GHC tarball:
Line 760 in c0525a2
It'd also likely be worthwhile to take a look at other usages of the system temp directory. On one hand, it seems odd to have a system configuration that has such limited space in tmp. On the other hand, I see few downsides to instead storing such temp directories somewhere in ~/.stack (and the big upside of resolving this issue)
Activity
LeifW commentedon Sep 16, 2015
Their article says tmpfs on Arch defaults to having its max size be half total RAM. https://wiki.archlinux.org/index.php/Tmpfs#Examples
snoyberg commentedon Sep 16, 2015
The downside to not using a proper temp directory is that if the process fails halfway through, the disk space is never reclaimed.
LeifW commentedon Sep 16, 2015
If that's a concern, what about using say https://hackage.haskell.org/package/temporary-1.2.0.3/docs/System-IO-Temp.html#v:withSystemTempDirectory ? Or are you referring to the Haskell process crashing?
snoyberg commentedon Sep 16, 2015
I'm referring to the Haskell process crashing (or system simply shutting down). And that's the function we're using already; the problem is Arch's setup not providing enough disk space in the temp directory.
LeifW commentedon Sep 16, 2015
I think other distros using systemd will have /tmp be tmpfs, too (edit: Sorry, apparently that's not the case. e.g. I don't think RedHat / CentOS have this; maybe just Arch and CentOS?). E.g. Fedora since version 18. http://fedoraproject.org/wiki/Features/tmp-on-tmpfs
mgsloan commentedon Sep 16, 2015
I figured we'd have stack check for that and free it up. This way, the only case where disk space is never reclaimed is if stack isn't run again. Could get a bit tricky with concurrent stack executions, though..
LeifW commentedon Sep 16, 2015
That Fedora page mentions a workaround:
getTemporaryDirectoryrespects$TMPDIR, so one could override the default of/tmpon systems that have issues withTMPDIR=/var/tmp stack ...That Fedora page suggests applications needing to write large files to/tmpshould use/var/tmpinstead, or maybe "XDG user-dir's Download directory". It sounds like there's a cron job cleaning out /var/tmp, too?If indeed /var/tmp is supposed to become some standard alternative to /tmp for large files; it makes one think there ought to be similar env vars for referencing it, and a corresponding method in System.Directory for getting its value in some cross-platform way?
mgsloan commentedon Sep 17, 2015
I've just noticed that there are a couple other related issues:
#623
#841 (this one mentions the
TMPDIRworkaround)LeifW commentedon Sep 17, 2015
http://fedoraproject.org/wiki/Features/tmp-on-tmpfs#Detailed_Description says /tmp on tmpfs is becoming more common.
I was thinking it would go away on its own as the average system gradually got more memory, but I forgot about VPS's. Also, I'm wondering when that space is reclaimed - filling up your RAM with large files would be unhelpful while you're running a compiler.
Not sure of a cross-platform way of specifying /var/tmp; seems like that functionality might belong in System.Directory, anyways. Perhaps we could just check if it exists. Proposed behaviour: Check for
$TMPDIR(to still allow override of location), check if /var/tmp exists (and is writeable), and finally fall back togetTemporaryDirectory(/tmp).Though, articles I read seem to dissuade /tmp and /var/tmp (especially when not being used to communicate between processes) due to security concerns, and suggest something like XDG user dirs (or somewhere in
~/.stackseems perfect for that).harendra-kumar commentedon Nov 9, 2015
I just ran into this issue. I have a VM setup where the root fs is mounted readonly and (therefore) /tmp is mounted as tmpfs with limited amount of space available. There is sufficient space available in /var/tmp though.
I know of at least one big installation where many systems are booted from the same image which is mounted over NFS. In such cases /tmp is mounted as a RAM file system. Though usually in enterprise settings the available RAM is usually enough to provide sufficient space but I guess there may be cases where /tmp is limited in space. However /var/tmp should usually have enough space. Preferring /var/tmp over /tmp might be a good idea.
rrnewton commentedon Nov 13, 2015
Unfortunately,
~/.stackis usually NFS for any of our user accounts and thus a lot slower than/tmp/...It sounds like there's a strong need for a portable way of finding a tmp directory that's on local disk, not in memory, and not on the network.
borsboom commentedon Nov 30, 2015
There doesn't seem to be any perfect solution to this, but I think writing big temporary files under
~/.stackis going to be the best default.Advantages:
/tmpon tmpfs is increasingly common/tmpand/var/tmprecommended only for inter-process communicationDisadvantages:
stack setupso it won't be a drag on every-day performance~/.stackgets big fast, so this will only make it happen a bit soonerWe must ensure any error messages about disk space are clear and offer workarounds.
harendra-kumar commentedon Nov 30, 2015
Sounds good.
Can we first check the amount of space available in a given volume before we try another one? We can try /tmp, $HOME, /var/tmp in that order based on the amount of space available. That way we will be able to try our best and bail out only if it is not at all possible to install. Space check will also allow us to provide a way to gracefully exit with an error message rather than trying and running out of space.
mgsloan commentedon Jan 3, 2016
Another reason to manage our own tmp directory is that we can make the process invocations in the verbose log copy+pasteable. Currently, some commands don't work due to the temporary files being eagerly deletd. See the first point of #1596 for more info.
xzinkus commentedon Mar 13, 2016
Note that you need an absolute path e.g.
TMPDIR=/home/user/tmpin some instancesmgsloan commentedon Aug 9, 2016
I've fixed this! The downside is that now there will be dirs leftover that the user will need to cleanup (unless they try to do setup again). This is even the case where stack gets to handle the exceptions, etc. The reason for this is that configure errors + etc say things like
Seeconfig.log' for more details` - it's convenient for the user to be able to manually run the command:Avoid unpacking ghc to /tmp #996
Don't use system temp dir for stack setup #996
Avoid unpacking ghc to /tmp #996
ruuda commentedon Nov 5, 2016
I am now experiencing the exact opposite issue:
stack setupfails because there is no space left on the disk that contains$LOCALAPPDATA\Programs\stack, but I have other disks with plenty of space. My home directory is on a small SSD that contains only my operating system and a few critical files. Unfortunately it is not possible on Windows to move the home directory after installation, so I am stuck with$LOCALAPPDATA\Programs\stackliving on the small disk.I tried the following:
$STACK_ROOTto be on a different disk. This works fine for most stuff, the index and snapshots are stored there, but not the download.$TMPto a directory on a different disk, as indicated in the FAQ. However, Stack still downloads to$LOCALAPPDATA\Programs\stack.$LOCALAPPDATAto a custom temporary directory when runningstack setup. This allowed the download to complete, but then Stack went on to actually install GHC in that location, not in$STACK_ROOT.To be able to support both the original scenario in this issue and the case of a small (or slow for that matter, as mentioned before here too) home directory, it would be nice if the download location were configurable. As there is
TMPDIRalready, would that be a good way to override the default download location?And shouldn’t GHC be installed to
$STACK_ROOT?mgsloan commentedon Nov 7, 2016
@ruuda That is a known issue, contribution appreciated! #1644
Update outdated FAQ entry on temp dirs
ruuda commentedon Nov 8, 2016
@mgsloan: Thanks for pointing me in the right direction. I opened #2766.
Update outdated FAQ entry on temp dirs