search for: preallocated

Hi All I was reading through this: http://kashyapc.com/2011/12/02/little-more-disk-io-perf-improvement-with-fallocateing-a-qcow2-disk/ I was basically searching for pointers on improving disk I/O. I wanted to know the purpose of preallocation=full & preallocation=metadata , What is the difference between them ? and which one would yield a better disk I/O speed ? Appreciate your

For raw, this allows "off" as a synonym for "sparse" (to make it consistent with qcow2). For qcow2, this allows "sparse" as a synonym for "off". It also adds qcow2 "full" preallocation, which is actually mapped to the qemu option "falloc" (see arguments about this on the qemu-devel mailing list, which we lost). This also updates the

On Tue, Jun 02, 2015 at 09:14:03AM +0530, Jatin Davey wrote: > Hi All > > I was reading through this: > > http://kashyapc.com/2011/12/02/little-more-disk-io-perf-improvement-with-fallocateing-a-qcow2-disk/ In my testing, the above method gives near-raw performance as it preallocated all the space ahead of time. The above test can now be done in a single command -- see option (3) below. > I was basically searching for pointers on improving disk I/O. > > I wanted to know the purpose of preallocation=full & preallocation=metadata > > > , What is the diffe...

Hi All, When I tried to create preallocated image with gluster , I am unable to create one The image gets created but not preallocated. [root@ ]# qemu-img create -f qcow2 -o preallocation=full gluster://host1.lab.eng.blr.redhat.com/rep3vol/vm3.img 3G Formatting 'gluster://dhcp37-61.lab.eng.blr.redhat.com/rep3vol/newvm3.img', fmt...

...o the inalloca design <https://llvm.org/docs/InAlloca.html>, there should be a stackrestore after an invoke in both the non-exceptional and exceptional case (that doesn't seem to be happening in some cases as we've seen, but that's beside the point). Does it make sense to model a preallocated call as handling the cleanup of the stack in normal control flow (e.g. always for a normal call, and in the non-exceptional path for an invoke)? Then @llvm.call.preallocated.teardown is only necessary in the exceptional path to cleanup the stack. On Thu, Apr 16, 2020 at 1:40 PM Eli Friedman <ef...

...--sparse together have broken --preallocate by itself (commit f3873b3d88b61167b106e7b9227a20147f8f6197) The previous behavior of --preallocate was to do just that: reserve blocks in the filesystem WITHOUT setting the size of the file to the final length. The reported filesize would change as the preallocated blocks were actually written. Unfortunately, the change causes a whole bunch of problems with our automated backup, and in particular with --append-verify or --inplace. The normal sequence we use in our large-file backup system is to combine preallocate with append-verify. When a partially writt...

When creating qcow2 images using virt-builder, is there a way to specify the qcow2 preallocation, as possible with qemu-img create -o preallocation=metada , for example? TIA, Y.

On Tue, May 17, 2016 at 05:53:31PM +0300, Yaniv Kaul wrote: > On Tue, May 17, 2016 at 5:48 PM, Richard W.M. Jones <rjones@redhat.com> > wrote: > > > On Tue, May 17, 2016 at 03:41:53PM +0100, Richard W.M. Jones wrote: > > > On Tue, May 17, 2016 at 05:15:57PM +0300, Yaniv Kaul wrote: > > > > When creating qcow2 images using virt-builder, is there a way to

I've read in Phil Spector's new book that it's a good idea to preallocate a big matrix, like u <- matrix(0,nrow,ncol) # (1) Now, I read contents of a huge matrix from a Fortran binary dump. u <- readBin(con,what="double",n=nrow*ncol) # (2) If I do (1) and then (2), u is a vector, obviously it's either reallocated or its matrix nature is lost -- overridden?

On Tue, May 17, 2016 at 03:41:53PM +0100, Richard W.M. Jones wrote: > On Tue, May 17, 2016 at 05:15:57PM +0300, Yaniv Kaul wrote: > > When creating qcow2 images using virt-builder, is there a way to specify > > the qcow2 preallocation, as possible with qemu-img create -o > > preallocation=metada , for example? > > No .. but .. it does default to preallocation=metadata

...at 2:20 PM Eli Friedman <efriedma at quicinc.com> wrote: > This would specifically be for cases where we try to rewrite the > signature? I would assume we should forbid rewriting the signature of a > call with an operand bundle. And once some optimization drops the bundle > and preallocated marking, to allow such rewriting, the signature doesn’t > need to match anymore. > Yes, I really would like to enable DAE and other signature rewriting IPO transforms. Maybe today DAE doesn't run on calls with bundles, but this feature is designed to allow the non-preallocated arguments...

Hi folks I am trying to install CentOS 5.2 in Vmware Server environment. In my VM disk space is not preallocated for the virtual disk (dynamically). The installer doesn't find the disk. When preallocating 6 GB there is no problem. See screenshot[0] Any ideas? kind regards Sven [0] http://bayimg.com/image/lamidaabe.jpg

https://bugzilla.samba.org/show_bug.cgi?id=8775 Summary: Preallocate option doesn't work with recursive? Product: rsync Version: 3.1.0 Platform: x64 OS/Version: Linux Status: NEW Severity: normal Priority: P5 Component: core AssignedTo: wayned at samba.org ReportedBy: wgordonharris at

...with the contents of the file matched from fuzzy_distance(). This would keep the destination file from being severely fragmented. What I see happening is rsync doing a local file copy first, but not block by block. When you copy a file on Windows, with the copy command, the entire file (size) is preallocated so that no fragmentation occurs. After this step, the copy command performs the actual transfer of data from the source file to the destination file. You could think of this almost as a local, non-fragmenting file copy operation, and then the rsync algorithm is used to update the new, destination...

When I use the preallocate patch and create a 77GB file using the function I get a CPU spike on the server-side. The spike lasts about 20 minutes and uses about 20%-25% of the cpu associated with the rsync instance creating the file. The spike is directly linked to the time it takes to create the file. I compiled rsync using cygwin CVS. I initially suspected the implementation of

On Tue, May 17, 2016 at 6:01 PM, Richard W.M. Jones <rjones@redhat.com> wrote: > On Tue, May 17, 2016 at 05:53:31PM +0300, Yaniv Kaul wrote: > > On Tue, May 17, 2016 at 5:48 PM, Richard W.M. Jones <rjones@redhat.com> > > wrote: > > > > > On Tue, May 17, 2016 at 03:41:53PM +0100, Richard W.M. Jones wrote: > > > > On Tue, May 17, 2016 at

...andom thoughts in no particular order. It would be nice to use `-oa sparse' etc for compatibility with virt-v2v, but that possibly closes off future options for replacing the horrible OCaml Arg module with GNU getopt_long (-oa == -o + -a). I initially tried to implement `--output-alloc sparse|preallocated' using the Planner. I added an extra planner flag [`Alloc, ("sparse"|"preallocated")]. I added extra transitions such as `Copy_sparse_never ("cp --sparse=never"). The problem is that some output locations don't support sparse output, eg. writing to a block d...

Hi Timo, Any chance the mbox/mdbox writer code could be modified to do physical preallocation on files to help avoid file(system) fragmentation? Constantly appending a file is the prime recipe for causing fragmentation, and mbox is notorious for this--not a fault of Dovecot but the nature of the mbox beast. Obviously maildir doesn't have such a problem, but some (many?) of us still prefer

...nowing about it, there is no reason to add a new way to do the same thing. Thanks, Reid The last RFC: http://lists.llvm.org/pipermail/llvm-dev/2013-July/064218.html Current inalloca docs: https://llvm.org/docs/InAlloca.html ---------------- # RFC: Replace inalloca with llvm.call.setup and preallocated In order to pass non-trivially copyable objects by value in a way that is compatible with the Visual C++ compiler on 32-bit x86, Clang has to be able to separate the allocation of call argument memory from the call site. The `inalloca` feature was added to LLVM for this purpose. However, this feat...

...*) - (* What output preallocation mode should we use? *) - let preallocation = - match t.target_format, cmdline.output_alloc with - | ("raw"|"qcow2"), Sparse -> Some "sparse" - | ("raw"|"qcow2"), Preallocated -> Some "full" - | _ -> None (* ignore -oa flag for other formats *) in - let compat = - match t.target_format with "qcow2" -> Some "1.1" | _ -> None in - output#disk_create filename t.target_format -...