Re: [libvirt RFC] add API for parallel Saves (not for committing)

RFC, starting point for discussion. Sketch API changes to allow parallel Saves, and open up and implementation for QEMU to leverage multifd migration to files, with optional multifd compression. This allows to improve save times for huge VMs. The idea is to issue commands like: virsh save domain /path/savevm --parallel --parallel-connections 2 and have libvirt start a multifd migration to: /path/savevm : main migration connection /path/savevm.1 : multifd channel 1 /path/savevm.2 : multifd channel 2

Signed-off-by: Claudio Fontana <cfontana(a)suse.de&gt; --- include/libvirt/libvirt-domain.h | 5 +++++ src/driver-hypervisor.h | 7 +++++++ src/libvirt_public.syms | 5 +++++ src/qemu/qemu_driver.c | 1 + tools/virsh-domain.c | 8 ++++++++ 5 files changed, 26 insertions(+) diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h index 2d5718301e..a7b9c4132d 100644 --- a/include/libvirt/libvirt-domain.h +++ b/include/libvirt/libvirt-domain.h @@ -1270,6 +1270,7 @@ typedef enum { VIR_DOMAIN_SAVE_RUNNING = 1 << 1, /* Favor running over paused */ VIR_DOMAIN_SAVE_PAUSED = 1 << 2, /* Favor paused over running */ VIR_DOMAIN_SAVE_RESET_NVRAM = 1 << 3, /* Re-initialize NVRAM from template */ + VIR_DOMAIN_SAVE_PARALLEL = 1 << 4, /* Parallel Save/Restore to multiple files */ } virDomainSaveRestoreFlags; int virDomainSave (virDomainPtr domain, @@ -1278,6 +1279,10 @@ int virDomainSaveFlags (virDomainPtr domain, const char *to, const char *dxml, unsigned int flags); +int virDomainSaveParametersFlags (virDomainPtr domain, + virTypedParameterPtr params, + int nparams, + unsigned int flags); int virDomainRestore (virConnectPtr conn, const char *from); int virDomainRestoreFlags (virConnectPtr conn, diff --git a/src/driver-hypervisor.h b/src/driver-hypervisor.h index 4423eb0885..a4e1d21e76 100644 --- a/src/driver-hypervisor.h +++ b/src/driver-hypervisor.h @@ -240,6 +240,12 @@ typedef int const char *dxml, unsigned int flags); +typedef int +(*virDrvDomainSaveParametersFlags)(virDomainPtr domain, + virTypedParameterPtr params, + int nparams, + unsigned int flags); + typedef int (*virDrvDomainRestore)(virConnectPtr conn, const char *from); @@ -1489,6 +1495,7 @@ struct _virHypervisorDriver { virDrvDomainGetControlInfo domainGetControlInfo; virDrvDomainSave domainSave; virDrvDomainSaveFlags domainSaveFlags; + virDrvDomainSaveParametersFlags domainSaveParametersFlags; virDrvDomainRestore domainRestore; virDrvDomainRestoreFlags domainRestoreFlags; virDrvDomainSaveImageGetXMLDesc domainSaveImageGetXMLDesc; diff --git a/src/libvirt_public.syms b/src/libvirt_public.syms index f93692c427..eb3a7afb75 100644 --- a/src/libvirt_public.syms +++ b/src/libvirt_public.syms @@ -916,4 +916,9 @@ LIBVIRT_8.0.0 { virDomainSetLaunchSecurityState; } LIBVIRT_7.8.0; +LIBVIRT_8.3.0 { + global: + virDomainSaveParametersFlags; +} LIBVIRT_8.0.0; + # .... define new API here using predicted next version number .... diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 77012eb527..249105356c 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -20826,6 +20826,7 @@ static virHypervisorDriver qemuHypervisorDriver = { .domainGetControlInfo = qemuDomainGetControlInfo, /* 0.9.3 */ .domainSave = qemuDomainSave, /* 0.2.0 */ .domainSaveFlags = qemuDomainSaveFlags, /* 0.9.4 */ + .domainSaveParametersFlags = qemuDomainSaveParametersFlags, /* 8.3.0 */ .domainRestore = qemuDomainRestore, /* 0.2.0 */ .domainRestoreFlags = qemuDomainRestoreFlags, /* 0.9.4 */ .domainSaveImageGetXMLDesc = qemuDomainSaveImageGetXMLDesc, /* 0.9.4 */ diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c index d5fd8be7c3..ccded6d265 100644 --- a/tools/virsh-domain.c +++ b/tools/virsh-domain.c @@ -4164,6 +4164,14 @@ static const vshCmdOptDef opts_save[] = { .type = VSH_OT_BOOL, .help = N_("avoid file system cache when saving") }, + {.name = "parallel", + .type = VSH_OT_BOOL, + .help = N_("enable parallel save to files") + }, + {.name = "parallel-connections", + .type = VSH_OT_INT, + .help = N_("number of connections/files for parallel save") + }, {.name = "xml", .type = VSH_OT_STRING, .completer = virshCompletePathLocalExisting, -- 2.34.1