Re: [libvirt] [PATCH] support compressed crashdump of guests

Now, virsh dump doesn't support compresses dump. This patch adds GZIP and LZOP option to virsh dump and support it at qemu coredump. (AFAIK, LZOP is available on RHEL6.) When I did 4G guest dump, (Raw) 3844669750 (Gzip) 1029846577 (LZOP) 1416263880 (faster than gzip in general) This will be a help for a host where crash-dump is used and several guests works on it. help message is modified as this. NAME dump - dump the core of a domain to a file for analysis SYNOPSIS dump [--live] [--crash] [--gzip] [--lzop] <domain> <file> DESCRIPTION Core dump a domain. OPTIONS --live perform a live core dump if supported --crash crash the domain after core dump --gzip gzip dump(only one compression allowed --lzop lzop dump(only one compression allowed [--domain] <string> domain name, id or uuid [--file] <string> where to dump the core Tested on Fedora-13+x86-64. Note: for better compression, we may have to skip pages filled by zero or freed pages. But it seems it's qemu's works.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com&gt; --- include/libvirt/libvirt.h.in | 2 ++ src/qemu/qemu_driver.c | 23 +++++++++++++++++++---- tools/virsh.c | 10 +++++++++- 3 files changed, 30 insertions(+), 5 deletions(-) Index: libvirt-0.8.4/src/qemu/qemu_driver.c =================================================================== --- libvirt-0.8.4.orig/src/qemu/qemu_driver.c +++ libvirt-0.8.4/src/qemu/qemu_driver.c @@ -5710,7 +5710,7 @@ cleanup: static int qemudDomainCoreDump(virDomainPtr dom, const char *path, - int flags ATTRIBUTE_UNUSED) { + int flags) { struct qemud_driver *driver = dom->conn->privateData; virDomainObjPtr vm; int resume = 0, paused = 0; @@ -5720,6 +5720,14 @@ static int qemudDomainCoreDump(virDomain "cat", NULL, }; + const char *zargs[] = { + "gzip", + NULL, + }; + const char *lzargs[] = { + "lzop", + NULL, + }; qemuDomainObjPrivatePtr priv; qemuDriverLock(driver); @@ -5787,9 +5795,16 @@ static int qemudDomainCoreDump(virDomain } qemuDomainObjEnterMonitorWithDriver(driver, vm); - ret = qemuMonitorMigrateToFile(priv->mon, - QEMU_MONITOR_MIGRATE_BACKGROUND, - args, path, 0); + if (flags & VIR_DUMP_GZIP) + ret = qemuMonitorMigrateToFile(priv->mon, + QEMU_MONITOR_MIGRATE_BACKGROUND, zargs, path, 0); + else if (flags & VIR_DUMP_LZOP) + ret = qemuMonitorMigrateToFile(priv->mon, + QEMU_MONITOR_MIGRATE_BACKGROUND, lzargs, path, 0); + else + ret = qemuMonitorMigrateToFile(priv->mon, + QEMU_MONITOR_MIGRATE_BACKGROUND, args, path, 0); +

qemuDomainObjExitMonitorWithDriver(driver, vm); if (ret < 0) goto endjob; Index: libvirt-0.8.4/tools/virsh.c =================================================================== --- libvirt-0.8.4.orig/tools/virsh.c +++ libvirt-0.8.4/tools/virsh.c @@ -1751,6 +1751,8 @@ static const vshCmdInfo info_dump[] = { static const vshCmdOptDef opts_dump[] = { {"live", VSH_OT_BOOL, 0, N_("perform a live core dump if supported")}, {"crash", VSH_OT_BOOL, 0, N_("crash the domain after core dump")}, + {"gzip", VSH_OT_BOOL, 0, N_("gzip dump(only one compression allowed")}, + {"lzop", VSH_OT_BOOL, 0, N_("lzop dump(only one compression allowed")},

{"domain", VSH_OT_DATA, VSH_OFLAG_REQ, N_("domain name, id or uuid")}, {"file", VSH_OT_DATA, VSH_OFLAG_REQ, N_("where to dump the core")}, {NULL, 0, 0, NULL} @@ -1778,7 +1780,13 @@ cmdDump(vshControl *ctl, const vshCmd *c flags |= VIR_DUMP_LIVE; if (vshCommandOptBool (cmd, "crash")) flags |= VIR_DUMP_CRASH; - + if (vshCommandOptBool (cmd, "gzip")) + flags |= VIR_DUMP_GZIP; + if (vshCommandOptBool (cmd, "lzop")) + flags |= VIR_DUMP_LZOP; + if ((flags & (VIR_DUMP_GZIP | VIR_DUMP_LZOP)) + == (VIR_DUMP_GZIP | VIR_DUMP_LZOP)) + return FALSE;