rp- commented on code in PR #14194:
URL: https://github.com/apache/cloudstack/pull/14194#discussion_r4324675071
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agent/src/main/java/com/cloud/agent/properties/AgentProperties.java:
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@@ -636,6 +636,42 @@ public class AgentProperties{
*/
public static final Property<String> KVM_SCRIPTS_DIR = new
Property<>("kvm.scripts.dir", "scripts/vm/hypervisor/kvm");
+ /**
+ * Host-local parent directory for the NAS backup pull-mode scratch area:
the NBD socket and
+ * the libvirt-managed fleecing (copy-before-write) images used while
backing up a running VM
+ * on raw block-device storage such as LINSTOR/DRBD.
+ * <p>
+ * Must be on a real on-disk filesystem with room for the guest's write
churn during a backup,
+ * and must NOT be on the NAS share: copy-before-write runs inline with
guest writes, so a slow
+ * or remote location stalls the VM. Keep the path short — the resulting
socket path is subject
+ * to the kernel's 108-byte UNIX socket limit.
+ * <p>
+ * Data type: String.<br>
+ * Default value: <code>/var/tmp</code>
+ *
+ * @since 4.22.0
+ */
+ public static final Property<String> NAS_BACKUP_PULL_SCRATCH_DIR = new
Property<>("nas.backup.pull.scratch.dir", "/var/tmp");
+
+ /**
+ * Free space the NAS backup pull-mode scratch area ({@link
#NAS_BACKUP_PULL_SCRATCH_DIR}) must
+ * have before a backup starts, as a percentage of the VM's total disk
size. Otherwise the
+ * backup fails up front.
+ * <p>
+ * Copy-before-write saves every guest block that is overwritten during
the backup into the
+ * scratch area, at most once per block, so the total disk size is the
worst case. If the scratch
+ * area fills up anyway, the guest's writes fail and the VM is paused. 100
rules that out; the
Review Comment:
obsolete now with the dynamic scratch resource implementation
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