Aug 30, 2017 Depending on the vintage of the filesystem, the lfs command, which is used to manage lfs setstripe -1 .

As of Lustre 2.9 it is possible to set a default OST pool on the whole filesystem ( via " lfs setstripe " on the root directory) that is inherited for new files/directories

I have noticed some inconsistencies in the *lfs setstripe/getstripe *commands and *llapi_file_get_stripe(*) function.Notice in the lfs setstripe/getstripe example below that specifying 7 for the offset with lfs setstripe -i 7 results in lfs getstripe reporting lmm_stripe_offset=7. lfs setstripe -s 1m -c 8 dir1 € You can “pre-create” a file as a zero-length striped file by running€lfs setstripe€as part of your job script or as part of the I/O routine in your program. You can then write to that file later. Use lfs setstripe -c N /path/to/directory to set the default stripe count to N on directory, which will affect all new files in that directory only. If you only have a limited number of OSTs (4 in your case), or all of your files are huge (in the GB range in your case) then you can use -c -1 , which means "stripe over all OSTs", rather than an explicit stripe count. Lustre best practices III Use stripe count 1 for directories with many small files (default on our system) mkdir experiments lfs setstripe -c 1 experiments cd experiments tar -zxvf code.tgz Copy larger files to another directory with higher striping mkdir large_files lfs setstripe -c 16 large_files cp file large_files/ lfs setstripe stripy.txt -s 4M -o -1 -c 6 ls -la > stripy.txt lfs getstripe stripy.txt • Now try the same thing for a directory. First create a directory, then set its striping, then make a file within that directory.

Lfs setstripe

setstripe should just use --ost for this, and deprecate --ost-list as this option has only been around for a short time. lfs find uses --mdt to search for a specific mdt_index, but lfs getstripe and lfs migrate use --mdt Use lfs setstripe -c N /path/to/directory to set the default stripe count to N on directory, which will affect all new files in that directory only. If you only have a limited number of OSTs (4 in your case), or all of your files are huge (in the GB range in your case) then you can use -c -1 , which means "stripe over all OSTs", rather than an explicit stripe count. > lfs setstripe -c 50 -s 32m bigdir I/O Considerations.

1 rank per node; 22600 nodes; Buffered I/O; POSIX file-per-process mode; Random file placement using "lfs setstripe -c 1"; Transfer size of 16MB; "-w -a POSIX

Lustre best practices III Use stripe count 1 for directories with many small files (default on our system) mkdir experiments lfs setstripe -c 1 experiments cd experiments tar -zxvf code.tgz Copy larger files to another directory with higher striping mkdir large_files lfs setstripe -c 16 large_files cp file large_files/ lfs setstripe – Display file striping patterns lfs getstripe [directory | file name] – Find file locations lfs find [directory | file name] Fltfidditifil tilOSTFor example, to find directories or files on a particular OST lfs find –r –obd ost5_UUID /work/rns – Disppyqlay quota information lfs quota -u|g … using „lfs setstripe “ (think „touch“) •You can create a file with specific striping values from your application using MPI-IO (coming up later) •If you want to change the lustre settings on an exisiting file you have to copy it : lfs setstripe newfile cp oldfile newfile rm oldfile lfs setstripe stripy.txt -s 4M -o -1 -c 6 ls -la > stripy.txt lfs getstripe stripy.txt • Now try the same thing for a directory. First create a directory, then set its striping, then make a file within that directory. mkdir s; cd s; lfs setstripe . -s 4M -o -1 -c 6 ls -la > file.txt lfs getstripe file.txt One case use the command lfs osts to correlate the index to the name of an actual OST. The lmm_stripe_size value is the size of the stripe, in bytes, in this case 1048576 bytes or 1 MiB. While examining a file's striping parameters is nice, it is not particularly useful unless one can also change it, which can be done with the lfs setstripe lfs setstripe-c 4.

$ lfs setstripe -c 1 dir1. Figure 3.12 – Setting a Directory to No Striping. Striping across all OSTs. You can stripe across all the OSTs by using a stripe count of -1 along with the default values for stripe index and stripe size. The lfs setstripe command for striping across all OSTs is shown in Figure 3.13. $ lfs setstripe -c -1 dir1

which will stripe across all disks, in 4MB chunks. To stripe a file before it is created (i.e. to touch it):. [name@server ~]$ lfs setstripe -c ''count'' -s ''size'' ''/path/to/dir'' the parameters of the directory, you may run lfs setstripe on the name of the file to be created.

Striping (lfs getstripe/lfs setstripe). 2.
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Several lfs commands can be run with OST pools.

Sep 2, 2013 Lustre lets you control striping independently for each directory or file, using the lfs setstripe and lfs getstripe commands to control and view that

You can also define a layout for a directory. Once set on a directory, that layout is applied to every new file added to that directory, but not to existing files.

$ lfs setstripe /mnt/lustre/file1 131072-1 2 This creats a file striped on two OSTs with 128kB on each stripe. $ lfs setstripe -d /mnt/lustre/dir This deletes a default stripe pattern on dir. New files will use the default striping pattern created therein.

$ lfs setstripe -d /mnt/lustre/dir This deletes a default stripe pattern on dir. New files will use the default striping pattern created therein. The man pages are a good reference source for the lfs command man lfs lfs quota lfs setstripe. lfs examples. To find your user and group quota [k1234567@login1(rosalind) ~] lfs quota /mnt/lustre. A human readable version [k1234567@login1(rosalind) ~] lfs quota -h /mnt/lustre. $ lfs setstripe /mnt/lustre/file1 131072-1 2 This creats a file striped on two OSTs with 128kB on each stripe.

Then, you can write to that file later.