diff --git a/src/common/meta/src/distributed_time_constants.rs b/src/common/meta/src/distributed_time_constants.rs
index 4c4148f184af..2b2b84fff81a 100644
--- a/src/common/meta/src/distributed_time_constants.rs
+++ b/src/common/meta/src/distributed_time_constants.rs
@@ -33,5 +33,8 @@ pub const DATANODE_LEASE_SECS: u64 = REGION_LEASE_SECS;
 /// The lease seconds of metasrv leader.
 pub const META_LEASE_SECS: u64 = 3;
 
-// In a lease, there are two opportunities for renewal.
+/// In a lease, there are two opportunities for renewal.
 pub const META_KEEP_ALIVE_INTERVAL_SECS: u64 = META_LEASE_SECS / 2;
+
+/// The default mailbox round-trip timeout.
+pub const MAILBOX_RTT_SECS: u64 = 1;
diff --git a/src/meta-srv/src/procedure/region_migration/downgrade_leader_region.rs b/src/meta-srv/src/procedure/region_migration/downgrade_leader_region.rs
index 8e1185d7ee12..69952e6953c2 100644
--- a/src/meta-srv/src/procedure/region_migration/downgrade_leader_region.rs
+++ b/src/meta-srv/src/procedure/region_migration/downgrade_leader_region.rs
@@ -16,7 +16,7 @@ use std::any::Any;
 use std::time::Duration;
 
 use api::v1::meta::MailboxMessage;
-use common_meta::distributed_time_constants::REGION_LEASE_SECS;
+use common_meta::distributed_time_constants::{MAILBOX_RTT_SECS, REGION_LEASE_SECS};
 use common_meta::instruction::{
     DowngradeRegion, DowngradeRegionReply, Instruction, InstructionReply,
 };
@@ -31,7 +31,7 @@ use crate::handler::HeartbeatMailbox;
 use crate::procedure::region_migration::{Context, State};
 use crate::service::mailbox::Channel;
 
-const DOWNGRADE_LEADER_REGION_TIMEOUT: Duration = Duration::from_secs(1);
+const DOWNGRADE_LEADER_REGION_TIMEOUT: Duration = Duration::from_secs(MAILBOX_RTT_SECS);
 
 #[derive(Debug, Serialize, Deserialize)]
 pub struct DowngradeLeaderRegion {
@@ -159,7 +159,7 @@ impl DowngradeLeaderRegion {
             }
             Err(error::Error::MailboxTimeout { .. }) => {
                 let reason = format!(
-                    "Mailbox received timeout for downgrade leader region {region_id} on Datanode {:?}", 
+                    "Mailbox received timeout for downgrade leader region {region_id} on datanode {:?}", 
                     leader,
                 );
                 error::RetryLaterSnafu { reason }.fail()
diff --git a/src/meta-srv/src/procedure/region_migration/open_candidate_region.rs b/src/meta-srv/src/procedure/region_migration/open_candidate_region.rs
index 2e126625347f..496237d5b62b 100644
--- a/src/meta-srv/src/procedure/region_migration/open_candidate_region.rs
+++ b/src/meta-srv/src/procedure/region_migration/open_candidate_region.rs
@@ -18,6 +18,7 @@ use std::time::Duration;
 
 use api::v1::meta::MailboxMessage;
 use common_meta::ddl::utils::region_storage_path;
+use common_meta::distributed_time_constants::MAILBOX_RTT_SECS;
 use common_meta::instruction::{Instruction, InstructionReply, OpenRegion, SimpleReply};
 use common_meta::RegionIdent;
 use serde::{Deserialize, Serialize};
@@ -29,7 +30,7 @@ use crate::procedure::region_migration::downgrade_leader_region::DowngradeLeader
 use crate::procedure::region_migration::{Context, State};
 use crate::service::mailbox::Channel;
 
-const OPEN_CANDIDATE_REGION_TIMEOUT: Duration = Duration::from_secs(1);
+const OPEN_CANDIDATE_REGION_TIMEOUT: Duration = Duration::from_secs(MAILBOX_RTT_SECS);
 
 #[derive(Debug, Serialize, Deserialize)]
 pub struct OpenCandidateRegion;
@@ -152,7 +153,7 @@ impl OpenCandidateRegion {
                 } else {
                     error::RetryLaterSnafu {
                         reason: format!(
-                            "Region {region_id} is not opened by Datanode {:?}, error: {error:?}",
+                            "Region {region_id} is not opened by datanode {:?}, error: {error:?}",
                             candidate,
                         ),
                     }
@@ -161,7 +162,7 @@ impl OpenCandidateRegion {
             }
             Err(error::Error::MailboxTimeout { .. }) => {
                 let reason = format!(
-                    "Mailbox received timeout for open candidate region {region_id} on Datanode {:?}", 
+                    "Mailbox received timeout for open candidate region {region_id} on datanode {:?}", 
                     candidate,
                 );
                 error::RetryLaterSnafu { reason }.fail()
diff --git a/src/meta-srv/src/procedure/region_migration/upgrade_candidate_region.rs b/src/meta-srv/src/procedure/region_migration/upgrade_candidate_region.rs
index 4baa609a09a1..c31ae31520de 100644
--- a/src/meta-srv/src/procedure/region_migration/upgrade_candidate_region.rs
+++ b/src/meta-srv/src/procedure/region_migration/upgrade_candidate_region.rs
@@ -16,6 +16,7 @@ use std::any::Any;
 use std::time::Duration;
 
 use api::v1::meta::MailboxMessage;
+use common_meta::distributed_time_constants::MAILBOX_RTT_SECS;
 use common_meta::instruction::{Instruction, InstructionReply, UpgradeRegion, UpgradeRegionReply};
 use common_telemetry::warn;
 use serde::{Deserialize, Serialize};
@@ -69,7 +70,7 @@ impl State for UpgradeCandidateRegion {
 }
 
 impl UpgradeCandidateRegion {
-    const UPGRADE_CANDIDATE_REGION_RTT: Duration = Duration::from_secs(1);
+    const UPGRADE_CANDIDATE_REGION_RTT: Duration = Duration::from_secs(MAILBOX_RTT_SECS);
 
     /// Returns the timeout of the upgrade candidate region.
     ///
@@ -146,7 +147,7 @@ impl UpgradeCandidateRegion {
                 if error.is_some() {
                     return error::RetryLaterSnafu {
                         reason: format!(
-                            "Failed to upgrade the region {} on Datanode {:?}, error: {:?}",
+                            "Failed to upgrade the region {} on datanode {:?}, error: {:?}",
                             region_id, candidate, error
                         ),
                     }
@@ -157,7 +158,7 @@ impl UpgradeCandidateRegion {
                     exists,
                     error::UnexpectedSnafu {
                         violated: format!(
-                            "Expected region {} doesn't exist on Datanode {:?}",
+                            "Expected region {} doesn't exist on datanode {:?}",
                             region_id, candidate
                         )
                     }
@@ -166,7 +167,7 @@ impl UpgradeCandidateRegion {
                 if self.require_ready && !ready {
                     return error::RetryLaterSnafu {
                         reason: format!(
-                            "Candidate region {} still replaying the wal on Datanode {:?}",
+                            "Candidate region {} still replaying the wal on datanode {:?}",
                             region_id, candidate
                         ),
                     }
@@ -177,7 +178,7 @@ impl UpgradeCandidateRegion {
             }
             Err(error::Error::MailboxTimeout { .. }) => {
                 let reason = format!(
-                        "Mailbox received timeout for upgrade candidate region {region_id} on Datanode {:?}", 
+                        "Mailbox received timeout for upgrade candidate region {region_id} on datanode {:?}", 
                         candidate,
                     );
                 error::RetryLaterSnafu { reason }.fail()