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authorChunyan Liu <cyliu@suse.com>2014-06-30 14:29:58 +0800
committerStefan Hajnoczi <stefanha@redhat.com>2014-07-01 10:15:12 +0200
commit4ab1559085d688dddf4de77f1ead3102e243e668 (patch)
treec02aaa834a94aace2ef773462cea3b4829cc48a9 /tests
parent8698e110f8aa1cdf8ba1afdda8f2658333a4ab01 (diff)
qemu-img create: add 'nocow' option
Add 'nocow' option so that users could have a chance to set NOCOW flag to newly created files. It's useful on btrfs file system to enhance performance. Btrfs has low performance when hosting VM images, even more when the guest in those VM are also using btrfs as file system. One way to mitigate this bad performance is to turn off COW attributes on VM files. Generally, there are two ways to turn off NOCOW on btrfs: a) by mounting fs with nodatacow, then all newly created files will be NOCOW. b) per file. Add the NOCOW file attribute. It could only be done to empty or new files. This patch tries the second way, according to the option, it could add NOCOW per file. For most block drivers, since the create file step is in raw-posix.c, so we can do setting NOCOW flag ioctl in raw-posix.c only. But there are some exceptions, like block/vpc.c and block/vdi.c, they are creating file by calling qemu_open directly. For them, do the same setting NOCOW flag ioctl work in them separately. [Fixed up 082.out due to the new 'nocow' creation option --Stefan] Signed-off-by: Chunyan Liu <cyliu@suse.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'tests')
-rw-r--r--tests/qemu-iotests/082.out24
1 files changed, 24 insertions, 0 deletions
diff --git a/tests/qemu-iotests/082.out b/tests/qemu-iotests/082.out
index 28309a0327..413e7ef391 100644
--- a/tests/qemu-iotests/082.out
+++ b/tests/qemu-iotests/082.out
@@ -66,6 +66,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: create -f qcow2 -o ? TEST_DIR/t.qcow2 128M
Supported options:
@@ -77,6 +78,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: create -f qcow2 -o cluster_size=4k,help TEST_DIR/t.qcow2 128M
Supported options:
@@ -88,6 +90,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: create -f qcow2 -o cluster_size=4k,? TEST_DIR/t.qcow2 128M
Supported options:
@@ -99,6 +102,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: create -f qcow2 -o help,cluster_size=4k TEST_DIR/t.qcow2 128M
Supported options:
@@ -110,6 +114,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: create -f qcow2 -o ?,cluster_size=4k TEST_DIR/t.qcow2 128M
Supported options:
@@ -121,6 +126,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: create -f qcow2 -o cluster_size=4k -o help TEST_DIR/t.qcow2 128M
Supported options:
@@ -132,6 +138,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: create -f qcow2 -o cluster_size=4k -o ? TEST_DIR/t.qcow2 128M
Supported options:
@@ -143,6 +150,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: create -f qcow2 -o backing_file=TEST_DIR/t.qcow2,,help TEST_DIR/t.qcow2 128M
Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/t.qcow2,help' encryption=off cluster_size=65536 lazy_refcounts=off
@@ -247,6 +255,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: convert -O qcow2 -o ? TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
Supported options:
@@ -258,6 +267,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: convert -O qcow2 -o cluster_size=4k,help TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
Supported options:
@@ -269,6 +279,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: convert -O qcow2 -o cluster_size=4k,? TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
Supported options:
@@ -280,6 +291,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: convert -O qcow2 -o help,cluster_size=4k TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
Supported options:
@@ -291,6 +303,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: convert -O qcow2 -o ?,cluster_size=4k TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
Supported options:
@@ -302,6 +315,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: convert -O qcow2 -o cluster_size=4k -o help TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
Supported options:
@@ -313,6 +327,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: convert -O qcow2 -o cluster_size=4k -o ? TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
Supported options:
@@ -324,6 +339,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: convert -O qcow2 -o backing_file=TEST_DIR/t.qcow2,,help TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
qemu-img: Could not open 'TEST_DIR/t.qcow2.base': Could not open backing file: Could not open 'TEST_DIR/t.qcow2,help': No such file or directory
@@ -417,6 +433,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: amend -f qcow2 -o ? TEST_DIR/t.qcow2
Supported options:
@@ -428,6 +445,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: amend -f qcow2 -o cluster_size=4k,help TEST_DIR/t.qcow2
Supported options:
@@ -439,6 +457,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: amend -f qcow2 -o cluster_size=4k,? TEST_DIR/t.qcow2
Supported options:
@@ -450,6 +469,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: amend -f qcow2 -o help,cluster_size=4k TEST_DIR/t.qcow2
Supported options:
@@ -461,6 +481,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: amend -f qcow2 -o ?,cluster_size=4k TEST_DIR/t.qcow2
Supported options:
@@ -472,6 +493,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: amend -f qcow2 -o cluster_size=4k -o help TEST_DIR/t.qcow2
Supported options:
@@ -483,6 +505,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: amend -f qcow2 -o cluster_size=4k -o ? TEST_DIR/t.qcow2
Supported options:
@@ -494,6 +517,7 @@ encryption Encrypt the image
cluster_size qcow2 cluster size
preallocation Preallocation mode (allowed values: off, metadata)
lazy_refcounts Postpone refcount updates
+nocow Turn off copy-on-write (valid only on btrfs)
Testing: amend -f qcow2 -o backing_file=TEST_DIR/t.qcow2,,help TEST_DIR/t.qcow2