* Premature -ENOSPC on btrfs? @ 2011-04-29 23:48 Darrick J. Wong 2011-04-30 0:00 ` cwillu 0 siblings, 1 reply; 5+ messages in thread From: Darrick J. Wong @ 2011-04-29 23:48 UTC (permalink / raw) To: linux-btrfs; +Cc: linux-kernel Hi, I was giving btrfs (2.6.39-rc4) a quick tryout today and noticed some odd behavior when running a rather stupid test. First, I create a 1GB test fs, format it, and mount it. Then, I run the following command to create a huge file, truncate it, rewrite it, and report what size file got created. # while true; do dd if=/dev/zero of=/mnt/testfile bs=1024k; done This is roughly what I see in terms of file size after filtering out all the "dd: writing `/mnt/testfile': No space left on device" messages. 782237696 bytes (782 MB) copied, 16.5647 s, 47.2 MB/s 545259520 bytes (545 MB) copied, 14.061 s, 38.8 MB/s 780140544 bytes (780 MB) copied, 15.2959 s, 51.0 MB/s 933232640 bytes (933 MB) copied, 15.2241 s, 61.3 MB/s 827326464 bytes (827 MB) copied, 14.8383 s, 55.8 MB/s 931135488 bytes (931 MB) copied, 15.1554 s, 61.4 MB/s 936378368 bytes (936 MB) copied, 2.98301 s, 314 MB/s 393216000 bytes (393 MB) copied, 12.9202 s, 30.4 MB/s 387973120 bytes (388 MB) copied, 13.4906 s, 28.8 MB/s 932184064 bytes (932 MB) copied, 15.3356 s, 60.8 MB/s 785383424 bytes (785 MB) copied, 14.6429 s, 53.6 MB/s 927989760 bytes (928 MB) copied, 15.4386 s, 60.1 MB/s 833617920 bytes (834 MB) copied, 14.6289 s, 57.0 MB/s 936378368 bytes (936 MB) copied, 3.33651 s, 281 MB/s 393216000 bytes (393 MB) copied, 12.9689 s, 30.3 MB/s 389021696 bytes (389 MB) copied, 6.02794 s, 64.5 MB/s 294649856 bytes (295 MB) copied, 1.05144 s, 280 MB/s Strangely, df reports that free space remains, and I can even create a second file to fill the empty space, so clearly the fs isn't full yet. Is this the intended behavior of btrfs? ext4/vfat seem to produce the same size file every time. --D ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Premature -ENOSPC on btrfs? 2011-04-29 23:48 Premature -ENOSPC on btrfs? Darrick J. Wong @ 2011-04-30 0:00 ` cwillu 2011-04-30 0:16 ` Darrick J. Wong 0 siblings, 1 reply; 5+ messages in thread From: cwillu @ 2011-04-30 0:00 UTC (permalink / raw) To: djwong; +Cc: linux-btrfs, linux-kernel On Fri, Apr 29, 2011 at 5:48 PM, Darrick J. Wong <djwong@us.ibm.com> wrote: > Hi, > > I was giving btrfs (2.6.39-rc4) a quick tryout today and noticed some odd > behavior when running a rather stupid test. > > First, I create a 1GB test fs, format it, and mount it. Then, I run the > following command to create a huge file, truncate it, rewrite it, and report > what size file got created. > > # while true; do dd if=/dev/zero of=/mnt/testfile bs=1024k; done > > This is roughly what I see in terms of file size after filtering out all the > "dd: writing `/mnt/testfile': No space left on device" messages. > > 782237696 bytes (782 MB) copied, 16.5647 s, 47.2 MB/s > 545259520 bytes (545 MB) copied, 14.061 s, 38.8 MB/s > 780140544 bytes (780 MB) copied, 15.2959 s, 51.0 MB/s > 933232640 bytes (933 MB) copied, 15.2241 s, 61.3 MB/s > 827326464 bytes (827 MB) copied, 14.8383 s, 55.8 MB/s > 931135488 bytes (931 MB) copied, 15.1554 s, 61.4 MB/s > 936378368 bytes (936 MB) copied, 2.98301 s, 314 MB/s > 393216000 bytes (393 MB) copied, 12.9202 s, 30.4 MB/s > 387973120 bytes (388 MB) copied, 13.4906 s, 28.8 MB/s > 932184064 bytes (932 MB) copied, 15.3356 s, 60.8 MB/s > 785383424 bytes (785 MB) copied, 14.6429 s, 53.6 MB/s > 927989760 bytes (928 MB) copied, 15.4386 s, 60.1 MB/s > 833617920 bytes (834 MB) copied, 14.6289 s, 57.0 MB/s > 936378368 bytes (936 MB) copied, 3.33651 s, 281 MB/s > 393216000 bytes (393 MB) copied, 12.9689 s, 30.3 MB/s > 389021696 bytes (389 MB) copied, 6.02794 s, 64.5 MB/s > 294649856 bytes (295 MB) copied, 1.05144 s, 280 MB/s > > Strangely, df reports that free space remains, and I can even create a second > file to fill the empty space, so clearly the fs isn't full yet. Is this the > intended behavior of btrfs? ext4/vfat seem to produce the same size file > every time. https://btrfs.wiki.kernel.org/index.php/FAQ#if_your_device_is_small You'll want to use mixed block groups with such a small filesystem. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Premature -ENOSPC on btrfs? 2011-04-30 0:00 ` cwillu @ 2011-04-30 0:16 ` Darrick J. Wong 2011-04-30 0:24 ` cwillu 0 siblings, 1 reply; 5+ messages in thread From: Darrick J. Wong @ 2011-04-30 0:16 UTC (permalink / raw) To: cwillu; +Cc: linux-btrfs, linux-kernel On Fri, Apr 29, 2011 at 06:00:16PM -0600, cwillu wrote: > On Fri, Apr 29, 2011 at 5:48 PM, Darrick J. Wong <djwong@us.ibm.com> wrote: > > Hi, > > > > I was giving btrfs (2.6.39-rc4) a quick tryout today and noticed some odd > > behavior when running a rather stupid test. > > > > First, I create a 1GB test fs, format it, and mount it. Then, I run the > > following command to create a huge file, truncate it, rewrite it, and report > > what size file got created. > > > > # while true; do dd if=/dev/zero of=/mnt/testfile bs=1024k; done > > > > This is roughly what I see in terms of file size after filtering out all the > > "dd: writing `/mnt/testfile': No space left on device" messages. > > > > 782237696 bytes (782 MB) copied, 16.5647 s, 47.2 MB/s > > 545259520 bytes (545 MB) copied, 14.061 s, 38.8 MB/s > > 780140544 bytes (780 MB) copied, 15.2959 s, 51.0 MB/s > > 933232640 bytes (933 MB) copied, 15.2241 s, 61.3 MB/s > > 827326464 bytes (827 MB) copied, 14.8383 s, 55.8 MB/s > > 931135488 bytes (931 MB) copied, 15.1554 s, 61.4 MB/s > > 936378368 bytes (936 MB) copied, 2.98301 s, 314 MB/s > > 393216000 bytes (393 MB) copied, 12.9202 s, 30.4 MB/s > > 387973120 bytes (388 MB) copied, 13.4906 s, 28.8 MB/s > > 932184064 bytes (932 MB) copied, 15.3356 s, 60.8 MB/s > > 785383424 bytes (785 MB) copied, 14.6429 s, 53.6 MB/s > > 927989760 bytes (928 MB) copied, 15.4386 s, 60.1 MB/s > > 833617920 bytes (834 MB) copied, 14.6289 s, 57.0 MB/s > > 936378368 bytes (936 MB) copied, 3.33651 s, 281 MB/s > > 393216000 bytes (393 MB) copied, 12.9689 s, 30.3 MB/s > > 389021696 bytes (389 MB) copied, 6.02794 s, 64.5 MB/s > > 294649856 bytes (295 MB) copied, 1.05144 s, 280 MB/s > > > > Strangely, df reports that free space remains, and I can even create a second > > file to fill the empty space, so clearly the fs isn't full yet. Is this the > > intended behavior of btrfs? ext4/vfat seem to produce the same size file > > every time. > > https://btrfs.wiki.kernel.org/index.php/FAQ#if_your_device_is_small > > You'll want to use mixed block groups with such a small filesystem. The wiki seems dead, but the Google cache version implies that 2.6.37+ takes care of enabling mixed block groups already. I also pulled btrfsprogs git and built a new mkfs, but that didn't seem to solve anything. --D ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Premature -ENOSPC on btrfs? 2011-04-30 0:16 ` Darrick J. Wong @ 2011-04-30 0:24 ` cwillu 2011-04-30 0:30 ` Darrick J. Wong 0 siblings, 1 reply; 5+ messages in thread From: cwillu @ 2011-04-30 0:24 UTC (permalink / raw) To: djwong; +Cc: linux-btrfs, linux-kernel On Fri, Apr 29, 2011 at 6:16 PM, Darrick J. Wong <djwong@us.ibm.com> wrote: > On Fri, Apr 29, 2011 at 06:00:16PM -0600, cwillu wrote: >> On Fri, Apr 29, 2011 at 5:48 PM, Darrick J. Wong <djwong@us.ibm.com> wrote: >> > Hi, >> > >> > I was giving btrfs (2.6.39-rc4) a quick tryout today and noticed some odd >> > behavior when running a rather stupid test. >> > >> > First, I create a 1GB test fs, format it, and mount it. Then, I run the >> > following command to create a huge file, truncate it, rewrite it, and report >> > what size file got created. >> > >> > # while true; do dd if=/dev/zero of=/mnt/testfile bs=1024k; done >> > >> > This is roughly what I see in terms of file size after filtering out all the >> > "dd: writing `/mnt/testfile': No space left on device" messages. >> > >> > 782237696 bytes (782 MB) copied, 16.5647 s, 47.2 MB/s >> > 545259520 bytes (545 MB) copied, 14.061 s, 38.8 MB/s >> > 780140544 bytes (780 MB) copied, 15.2959 s, 51.0 MB/s >> > 933232640 bytes (933 MB) copied, 15.2241 s, 61.3 MB/s >> > 827326464 bytes (827 MB) copied, 14.8383 s, 55.8 MB/s >> > 931135488 bytes (931 MB) copied, 15.1554 s, 61.4 MB/s >> > 936378368 bytes (936 MB) copied, 2.98301 s, 314 MB/s >> > 393216000 bytes (393 MB) copied, 12.9202 s, 30.4 MB/s >> > 387973120 bytes (388 MB) copied, 13.4906 s, 28.8 MB/s >> > 932184064 bytes (932 MB) copied, 15.3356 s, 60.8 MB/s >> > 785383424 bytes (785 MB) copied, 14.6429 s, 53.6 MB/s >> > 927989760 bytes (928 MB) copied, 15.4386 s, 60.1 MB/s >> > 833617920 bytes (834 MB) copied, 14.6289 s, 57.0 MB/s >> > 936378368 bytes (936 MB) copied, 3.33651 s, 281 MB/s >> > 393216000 bytes (393 MB) copied, 12.9689 s, 30.3 MB/s >> > 389021696 bytes (389 MB) copied, 6.02794 s, 64.5 MB/s >> > 294649856 bytes (295 MB) copied, 1.05144 s, 280 MB/s >> > >> > Strangely, df reports that free space remains, and I can even create a second >> > file to fill the empty space, so clearly the fs isn't full yet. Is this the >> > intended behavior of btrfs? ext4/vfat seem to produce the same size file >> > every time. >> >> https://btrfs.wiki.kernel.org/index.php/FAQ#if_your_device_is_small >> >> You'll want to use mixed block groups with such a small filesystem. > > The wiki seems dead, but the Google cache version implies that 2.6.37+ takes > care of enabling mixed block groups already. I also pulled btrfsprogs git and > built a new mkfs, but that didn't seem to solve anything. The wiki does that frequently :( Check the tmp branch of the progs git; there should be a -M option to mkfs.btrfs. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Premature -ENOSPC on btrfs? 2011-04-30 0:24 ` cwillu @ 2011-04-30 0:30 ` Darrick J. Wong 0 siblings, 0 replies; 5+ messages in thread From: Darrick J. Wong @ 2011-04-30 0:30 UTC (permalink / raw) To: cwillu; +Cc: linux-btrfs, linux-kernel On Fri, Apr 29, 2011 at 06:24:16PM -0600, cwillu wrote: > On Fri, Apr 29, 2011 at 6:16 PM, Darrick J. Wong <djwong@us.ibm.com> wrote: > > On Fri, Apr 29, 2011 at 06:00:16PM -0600, cwillu wrote: > >> On Fri, Apr 29, 2011 at 5:48 PM, Darrick J. Wong <djwong@us.ibm.com> wrote: > >> > Hi, > >> > > >> > I was giving btrfs (2.6.39-rc4) a quick tryout today and noticed some odd > >> > behavior when running a rather stupid test. > >> > > >> > First, I create a 1GB test fs, format it, and mount it. Then, I run the > >> > following command to create a huge file, truncate it, rewrite it, and report > >> > what size file got created. > >> > > >> > # while true; do dd if=/dev/zero of=/mnt/testfile bs=1024k; done > >> > > >> > This is roughly what I see in terms of file size after filtering out all the > >> > "dd: writing `/mnt/testfile': No space left on device" messages. > >> > > >> > 782237696 bytes (782 MB) copied, 16.5647 s, 47.2 MB/s > >> > 545259520 bytes (545 MB) copied, 14.061 s, 38.8 MB/s > >> > 780140544 bytes (780 MB) copied, 15.2959 s, 51.0 MB/s > >> > 933232640 bytes (933 MB) copied, 15.2241 s, 61.3 MB/s > >> > 827326464 bytes (827 MB) copied, 14.8383 s, 55.8 MB/s > >> > 931135488 bytes (931 MB) copied, 15.1554 s, 61.4 MB/s > >> > 936378368 bytes (936 MB) copied, 2.98301 s, 314 MB/s > >> > 393216000 bytes (393 MB) copied, 12.9202 s, 30.4 MB/s > >> > 387973120 bytes (388 MB) copied, 13.4906 s, 28.8 MB/s > >> > 932184064 bytes (932 MB) copied, 15.3356 s, 60.8 MB/s > >> > 785383424 bytes (785 MB) copied, 14.6429 s, 53.6 MB/s > >> > 927989760 bytes (928 MB) copied, 15.4386 s, 60.1 MB/s > >> > 833617920 bytes (834 MB) copied, 14.6289 s, 57.0 MB/s > >> > 936378368 bytes (936 MB) copied, 3.33651 s, 281 MB/s > >> > 393216000 bytes (393 MB) copied, 12.9689 s, 30.3 MB/s > >> > 389021696 bytes (389 MB) copied, 6.02794 s, 64.5 MB/s > >> > 294649856 bytes (295 MB) copied, 1.05144 s, 280 MB/s > >> > > >> > Strangely, df reports that free space remains, and I can even create a second > >> > file to fill the empty space, so clearly the fs isn't full yet. Is this the > >> > intended behavior of btrfs? ext4/vfat seem to produce the same size file > >> > every time. > >> > >> https://btrfs.wiki.kernel.org/index.php/FAQ#if_your_device_is_small > >> > >> You'll want to use mixed block groups with such a small filesystem. > > > > The wiki seems dead, but the Google cache version implies that 2.6.37+ takes > > care of enabling mixed block groups already. I also pulled btrfsprogs git and > > built a new mkfs, but that didn't seem to solve anything. > > The wiki does that frequently :( > > Check the tmp branch of the progs git; there should be a -M option to > mkfs.btrfs. Yep, now I see it. That -M seems to have stabilized it a bit: 945815552 bytes (946 MB) copied, 1.90592 s, 496 MB/s 1034944512 bytes (1.0 GB) copied, 4.55472 s, 227 MB/s 946864128 bytes (947 MB) copied, 2.55459 s, 371 MB/s 957349888 bytes (957 MB) copied, 2.55406 s, 375 MB/s 956301312 bytes (956 MB) copied, 2.63751 s, 363 MB/s 956301312 bytes (956 MB) copied, 2.44889 s, 391 MB/s 956301312 bytes (956 MB) copied, 2.50232 s, 382 MB/s 956301312 bytes (956 MB) copied, 2.97849 s, 321 MB/s 956301312 bytes (956 MB) copied, 2.4995 s, 383 MB/s 956301312 bytes (956 MB) copied, 2.44848 s, 391 MB/s 956301312 bytes (956 MB) copied, 2.45217 s, 390 MB/s 956301312 bytes (956 MB) copied, 2.60435 s, 367 MB/s 956301312 bytes (956 MB) copied, 2.49104 s, 384 MB/s 956301312 bytes (956 MB) copied, 2.45969 s, 389 MB/s 956301312 bytes (956 MB) copied, 3.02976 s, 316 MB/s 956301312 bytes (956 MB) copied, 2.96214 s, 323 MB/s Still a little odd why the first four tries yield those results. --D ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2011-04-30 0:30 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2011-04-29 23:48 Premature -ENOSPC on btrfs? Darrick J. Wong 2011-04-30 0:00 ` cwillu 2011-04-30 0:16 ` Darrick J. Wong 2011-04-30 0:24 ` cwillu 2011-04-30 0:30 ` Darrick J. Wong
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