[Qemu-block] [PATCH RFC 1/7] docs/block-replication: Add description for shared-disk case
Introuduce the scenario of shared-disk block replication and how to use it. Signed-off-by: zhanghailiang Signed-off-by: Wen Congyang Signed-off-by: Zhang Chen --- docs/block-replication.txt | 131 +++-- 1 file changed, 127 insertions(+), 4 deletions(-) diff --git a/docs/block-replication.txt b/docs/block-replication.txt index 6bde673..97fcfc1 100644 --- a/docs/block-replication.txt +++ b/docs/block-replication.txt @@ -24,7 +24,7 @@ only dropped at next checkpoint time. To reduce the network transportation effort during a vmstate checkpoint, the disk modification operations of the Primary disk are asynchronously forwarded to the Secondary node. -== Workflow == +== Non-shared disk workflow == The following is the image of block replication workflow: +--+++ @@ -57,7 +57,7 @@ The following is the image of block replication workflow: 4) Secondary write requests will be buffered in the Disk buffer and it will overwrite the existing sector content in the buffer. -== Architecture == +== None-shared disk architecture == We are going to implement block replication from many basic blocks that are already in QEMU. @@ -106,6 +106,74 @@ any state that would otherwise be lost by the speculative write-through of the NBD server into the secondary disk. So before block replication, the primary disk and secondary disk should contain the same data. +== Shared Disk Mode Workflow == +The following is the image of block replication workflow: + ++--+++ +|Primary Write Requests||Secondary Write Requests| ++--+++ + | | + | (4) + | V + | /-\ + | (2)Forward and write through | | + | +--> | Disk Buffer | + | || | + | |\-/ + | |(1)read | + | | | + (3)write | | | backing file + V | | + +-+ | + | Shared Disk | <-+ + +-+ + +1) Primary writes will read original data and forward it to Secondary + QEMU. +2) Before Primary write requests are written to Shared disk, the + original sector content will be read from Shared disk and + forwarded and buffered in the Disk buffer on the secondary site, + but it will not overwrite the existing + sector content(it could be from either "Secondary Write Requests" or + previous COW of "Primary Write Requests") in the Disk buffer. +3) Primary write requests will be written to Shared disk. +4) Secondary write requests will be buffered in the Disk buffer and it + will overwrite the existing sector content in the buffer. + +== Shared Disk Mode Architecture == +We are going to implement block replication from many basic +blocks that are already in QEMU. + virtio-blk || .-- + / || | Secondary +/ || '-- + /|| virtio-blk + / || | + | || replication(5) + |NBD > NBD (2) | + | client ||server ---> hidden disk <-- active disk(4) + | ^ || | + | replication(1) || | + | | || | + | +-' || | + (3) |drive-backup sync=none || | +. | +-+ || | +Primary | | | || backing| +' | | || | + V | | + +---+| + | shared disk | <--+ +
Re: [Qemu-block] [PATCH RFC 1/7] docs/block-replication: Add description for shared-disk case
On 10/20/2016 09:57 PM, zhanghailiang wrote: Introuduce the scenario of shared-disk block replication and how to use it. Signed-off-by: zhanghailiang Signed-off-by: Wen Congyang Signed-off-by: Zhang Chen --- docs/block-replication.txt | 131 +++-- 1 file changed, 127 insertions(+), 4 deletions(-) diff --git a/docs/block-replication.txt b/docs/block-replication.txt index 6bde673..97fcfc1 100644 --- a/docs/block-replication.txt +++ b/docs/block-replication.txt @@ -24,7 +24,7 @@ only dropped at next checkpoint time. To reduce the network transportation effort during a vmstate checkpoint, the disk modification operations of the Primary disk are asynchronously forwarded to the Secondary node. -== Workflow == +== Non-shared disk workflow == The following is the image of block replication workflow: +--+++ @@ -57,7 +57,7 @@ The following is the image of block replication workflow: 4) Secondary write requests will be buffered in the Disk buffer and it will overwrite the existing sector content in the buffer. -== Architecture == +== None-shared disk architecture == s/None-shared/Non-shared/g We are going to implement block replication from many basic blocks that are already in QEMU. @@ -106,6 +106,74 @@ any state that would otherwise be lost by the speculative write-through of the NBD server into the secondary disk. So before block replication, the primary disk and secondary disk should contain the same data. +== Shared Disk Mode Workflow == +The following is the image of block replication workflow: + ++--+++ +|Primary Write Requests||Secondary Write Requests| ++--+++ + | | + | (4) + | V + | /-\ + | (2)Forward and write through | | + | +--> | Disk Buffer | + | || | + | |\-/ + | |(1)read | + | | | + (3)write | | | backing file + V | | + +-+ | + | Shared Disk | <-+ + +-+ + +1) Primary writes will read original data and forward it to Secondary + QEMU. +2) Before Primary write requests are written to Shared disk, the + original sector content will be read from Shared disk and + forwarded and buffered in the Disk buffer on the secondary site, + but it will not overwrite the existing extra spaces at the end of line + sector content(it could be from either "Secondary Write Requests" or Need a space before "(" for better style. + previous COW of "Primary Write Requests") in the Disk buffer. +3) Primary write requests will be written to Shared disk. +4) Secondary write requests will be buffered in the Disk buffer and it + will overwrite the existing sector content in the buffer. + +== Shared Disk Mode Architecture == +We are going to implement block replication from many basic +blocks that are already in QEMU. + virtio-blk || .-- + / || | Secondary +/ || '-- + /|| virtio-blk + / || | + | || replication(5) + |NBD > NBD (2) | + | client ||server ---> hidden disk <-- active disk(4) + | ^ || | + | replication(1) || | + | | || | + | +-' || | + (3) |drive-backup sync=none || | +. | +-+ || | +Primary | | | || backing| +' | | || | + V |
Re: [Qemu-block] [PATCH RFC 1/7] docs/block-replication: Add description for shared-disk case
On 2016/10/25 17:03, Changlong Xie wrote: On 10/20/2016 09:57 PM, zhanghailiang wrote: Introuduce the scenario of shared-disk block replication and how to use it. Signed-off-by: zhanghailiang Signed-off-by: Wen Congyang Signed-off-by: Zhang Chen --- docs/block-replication.txt | 131 +++-- 1 file changed, 127 insertions(+), 4 deletions(-) diff --git a/docs/block-replication.txt b/docs/block-replication.txt index 6bde673..97fcfc1 100644 --- a/docs/block-replication.txt +++ b/docs/block-replication.txt @@ -24,7 +24,7 @@ only dropped at next checkpoint time. To reduce the network transportation effort during a vmstate checkpoint, the disk modification operations of the Primary disk are asynchronously forwarded to the Secondary node. -== Workflow == +== Non-shared disk workflow == The following is the image of block replication workflow: +--+++ @@ -57,7 +57,7 @@ The following is the image of block replication workflow: 4) Secondary write requests will be buffered in the Disk buffer and it will overwrite the existing sector content in the buffer. -== Architecture == +== None-shared disk architecture == s/None-shared/Non-shared/g We are going to implement block replication from many basic blocks that are already in QEMU. @@ -106,6 +106,74 @@ any state that would otherwise be lost by the speculative write-through of the NBD server into the secondary disk. So before block replication, the primary disk and secondary disk should contain the same data. +== Shared Disk Mode Workflow == +The following is the image of block replication workflow: + ++--+++ +|Primary Write Requests||Secondary Write Requests| ++--+++ + | | + | (4) + | V + | /-\ + | (2)Forward and write through | | + | +--> | Disk Buffer | + | || | + | |\-/ + | |(1)read | + | | | + (3)write | | | backing file + V | | + +-+ | + | Shared Disk | <-+ + +-+ + +1) Primary writes will read original data and forward it to Secondary + QEMU. +2) Before Primary write requests are written to Shared disk, the + original sector content will be read from Shared disk and + forwarded and buffered in the Disk buffer on the secondary site, + but it will not overwrite the existing extra spaces at the end of line + sector content(it could be from either "Secondary Write Requests" or Need a space before "(" for better style. + previous COW of "Primary Write Requests") in the Disk buffer. +3) Primary write requests will be written to Shared disk. +4) Secondary write requests will be buffered in the Disk buffer and it + will overwrite the existing sector content in the buffer. + +== Shared Disk Mode Architecture == +We are going to implement block replication from many basic +blocks that are already in QEMU. + virtio-blk || .-- + / || | Secondary +/ || '-- + /|| virtio-blk + / || | + | || replication(5) + |NBD > NBD (2) | + | client ||server ---> hidden disk <-- active disk(4) + | ^ || | + | replication(1) || | + | | || | + | +-' || | + (3) |drive-backup sync=none || | +. | +-+ || | +Primary | | | || backing| +' | |
Re: [Qemu-block] [PATCH RFC 1/7] docs/block-replication: Add description for shared-disk case
On 11/28/2016 01:13 PM, Hailiang Zhang wrote: On 2016/10/25 17:03, Changlong Xie wrote: On 10/20/2016 09:57 PM, zhanghailiang wrote: Introuduce the scenario of shared-disk block replication and how to use it. Signed-off-by: zhanghailiang Signed-off-by: Wen Congyang Signed-off-by: Zhang Chen --- docs/block-replication.txt | 131 +++-- 1 file changed, 127 insertions(+), 4 deletions(-) diff --git a/docs/block-replication.txt b/docs/block-replication.txt index 6bde673..97fcfc1 100644 --- a/docs/block-replication.txt +++ b/docs/block-replication.txt @@ -24,7 +24,7 @@ only dropped at next checkpoint time. To reduce the network transportation effort during a vmstate checkpoint, the disk modification operations of the Primary disk are asynchronously forwarded to the Secondary node. -== Workflow == +== Non-shared disk workflow == The following is the image of block replication workflow: +--+ ++ @@ -57,7 +57,7 @@ The following is the image of block replication workflow: 4) Secondary write requests will be buffered in the Disk buffer and it will overwrite the existing sector content in the buffer. -== Architecture == +== None-shared disk architecture == s/None-shared/Non-shared/g We are going to implement block replication from many basic blocks that are already in QEMU. @@ -106,6 +106,74 @@ any state that would otherwise be lost by the speculative write-through of the NBD server into the secondary disk. So before block replication, the primary disk and secondary disk should contain the same data. +== Shared Disk Mode Workflow == +The following is the image of block replication workflow: + ++--+++ +|Primary Write Requests||Secondary Write Requests| ++--+++ + | | + | (4) + | V + | /-\ + | (2)Forward and write through | | + | +--> | Disk Buffer | + | || | + | |\-/ + | |(1)read | + | | | + (3)write | | | backing file + V | | + +-+ | + | Shared Disk | <-+ + +-+ + +1) Primary writes will read original data and forward it to Secondary + QEMU. +2) Before Primary write requests are written to Shared disk, the + original sector content will be read from Shared disk and + forwarded and buffered in the Disk buffer on the secondary site, + but it will not overwrite the existing extra spaces at the end of line + sector content(it could be from either "Secondary Write Requests" or Need a space before "(" for better style. + previous COW of "Primary Write Requests") in the Disk buffer. +3) Primary write requests will be written to Shared disk. +4) Secondary write requests will be buffered in the Disk buffer and it + will overwrite the existing sector content in the buffer. + +== Shared Disk Mode Architecture == +We are going to implement block replication from many basic +blocks that are already in QEMU. + virtio-blk || .-- + / || | Secondary +/ || '-- + / || virtio-blk + / || | + | || replication(5) + |NBD > NBD (2) | + | client ||server ---> hidden disk <-- active disk(4) + | ^ || | + | replication(1) || | + | | || | + | +-' || | + (3) |drive-backup sync=none || | +. | +-+ || | +Primary | | | || backing| +' | | || | + V | | + +
Re: [Qemu-block] [PATCH RFC 1/7] docs/block-replication: Add description for shared-disk case
On 2016/11/28 14:00, Changlong Xie wrote: On 11/28/2016 01:13 PM, Hailiang Zhang wrote: On 2016/10/25 17:03, Changlong Xie wrote: On 10/20/2016 09:57 PM, zhanghailiang wrote: Introuduce the scenario of shared-disk block replication and how to use it. Signed-off-by: zhanghailiang Signed-off-by: Wen Congyang Signed-off-by: Zhang Chen --- docs/block-replication.txt | 131 +++-- 1 file changed, 127 insertions(+), 4 deletions(-) diff --git a/docs/block-replication.txt b/docs/block-replication.txt index 6bde673..97fcfc1 100644 --- a/docs/block-replication.txt +++ b/docs/block-replication.txt @@ -24,7 +24,7 @@ only dropped at next checkpoint time. To reduce the network transportation effort during a vmstate checkpoint, the disk modification operations of the Primary disk are asynchronously forwarded to the Secondary node. -== Workflow == +== Non-shared disk workflow == The following is the image of block replication workflow: +--+ ++ @@ -57,7 +57,7 @@ The following is the image of block replication workflow: 4) Secondary write requests will be buffered in the Disk buffer and it will overwrite the existing sector content in the buffer. -== Architecture == +== None-shared disk architecture == s/None-shared/Non-shared/g We are going to implement block replication from many basic blocks that are already in QEMU. @@ -106,6 +106,74 @@ any state that would otherwise be lost by the speculative write-through of the NBD server into the secondary disk. So before block replication, the primary disk and secondary disk should contain the same data. +== Shared Disk Mode Workflow == +The following is the image of block replication workflow: + ++--+++ +|Primary Write Requests||Secondary Write Requests| ++--+++ + | | + | (4) + | V + | /-\ + | (2)Forward and write through | | + | +--> | Disk Buffer | + | || | + | |\-/ + | |(1)read | + | | | + (3)write | | | backing file + V | | + +-+ | + | Shared Disk | <-+ + +-+ + +1) Primary writes will read original data and forward it to Secondary + QEMU. +2) Before Primary write requests are written to Shared disk, the + original sector content will be read from Shared disk and + forwarded and buffered in the Disk buffer on the secondary site, + but it will not overwrite the existing extra spaces at the end of line + sector content(it could be from either "Secondary Write Requests" or Need a space before "(" for better style. + previous COW of "Primary Write Requests") in the Disk buffer. +3) Primary write requests will be written to Shared disk. +4) Secondary write requests will be buffered in the Disk buffer and it + will overwrite the existing sector content in the buffer. + +== Shared Disk Mode Architecture == +We are going to implement block replication from many basic +blocks that are already in QEMU. + virtio-blk || .-- + / || | Secondary +/ || '-- + / || virtio-blk + / || | + | || replication(5) + |NBD > NBD (2) | + | client ||server ---> hidden disk <-- active disk(4) + | ^ || | + | replication(1) || | + | | || | + | +-' || | + (3) |drive-backup sync=none || | +. | +-+ || | +Primary | | | || backing| +' | | || | + V |