dotnet/orleans · warning · OrleansException

SuspectingSilos.Length of

Error message

SuspectingSilos.Length of {0} as read from Azure table is not equal to SuspectingTimes.Length of {1}

What it means

Thrown by AzureBasedMembershipTable.Parse when the SuspectingSilos and SuspectingTimes pipe-delimited lists have different lengths. Membership uses these parallel lists to record which silos voted a peer as suspect and when; a length mismatch indicates a corrupt or partially-written entity. OrleansException (not ArgumentException) is thrown inside Parse and, because Parse is called within the per-entry try, is logged-and-ignored via LogErrorParsingMembershipTableDataIgnoring, so the offending entry is skipped rather than fatal.

Solutions

1. Inspect the offending entity's SuspectingSilos and SuspectingTimes fields and reconcile them (trim the longer list to match).
2. Let the table self-heal: because the entry is skipped, the next membership update will overwrite the suspector lists consistently.
3. Force a membership refresh (restart a silo or call CleanupDefunctSiloEntries) to re-stamp suspect data.
4. Avoid manual edits to suspector fields; they are written atomically by Orleans in normal operation.

Example fix

// remediation in Azure Storage Explorer
// entity RowKey=<silo>: set SuspectingSilos and SuspectingTimes to '' (empty)
// then let Orleans repopulate them on the next suspicion cycle

// validate suspector parallel lists before relying on them:
int silos = string.IsNullOrEmpty(entry.SuspectingSilos) ? 0 : entry.SuspectingSilos.Split('|').Length;
int times = string.IsNullOrEmpty(entry.SuspectingTimes) ? 0 : entry.SuspectingTimes.Split('|').Length;
if (silos != times) { /* skip or repair entry */ }

// Parse swallows this via LogErrorParsingMembershipTableDataIgnoring, so the entry is skipped.
// To detect: subscribe to the LogErrorParsingMembershipTableDataIgnoring log event and alert on it.

When it happens

Trigger: A membership table entity has SuspectingSilos with N entries and SuspectingTimes with M != N entries (split on '|'). Occurs when a silo crashed mid-write of those two fields, or when an external tool edited only one field.

Common situations: Silo crash between updating SuspectingSilos and SuspectingTimes; manual entity edits; storage serialization that dropped one field; mixed-version cluster writing fields with different separators.

Related errors

• Did not read table version row. Read =
• The membership table does not contain a version row.
• The table version row does not contain a membership version.
• Could not find table version row or found too many entries…
• The table version entry must have a membership version.

AI-assisted analysis of dotnet/orleans@fca799fa70 (2026-08-13). Data as JSON: /api/errors/857ea89ec7401b30. Report an issue: GitHub.

Appendix: source

Thrown at src/Azure/Orleans.Clustering.AzureStorage/AzureBasedMembershipTable.cs:276

            if (!string.IsNullOrEmpty(tableEntry.SuspectingSilos))
            {
                string[] silos = tableEntry.SuspectingSilos.Split('|');
                foreach (string silo in silos)
                {
                    suspectingSilos.Add(SiloAddress.FromParsableString(silo));
                }
            }

            if (!string.IsNullOrEmpty(tableEntry.SuspectingTimes))
            {
                string[] times = tableEntry.SuspectingTimes.Split('|');
                foreach (string time in times)
                    suspectingTimes.Add(LogFormatter.ParseDate(time));
            }

            if (suspectingSilos.Count != suspectingTimes.Count)
                throw new OrleansException(string.Format("SuspectingSilos.Length of {0} as read from Azure table is not equal to SuspectingTimes.Length of {1}", suspectingSilos.Count, suspectingTimes.Count));

            for (int i = 0; i < suspectingSilos.Count; i++)
                parse.AddSuspector(suspectingSilos[i], suspectingTimes[i]);

            return parse;
        }

        private static SiloInstanceTableEntry Convert(MembershipEntry memEntry, string deploymentId)
        {
            var tableEntry = new SiloInstanceTableEntry
            {
                DeploymentId = deploymentId,
                Address = memEntry.SiloAddress.Endpoint.Address.ToString(),
                Port = memEntry.SiloAddress.Endpoint.Port.ToString(CultureInfo.InvariantCulture),
                Generation = memEntry.SiloAddress.Generation.ToString(CultureInfo.InvariantCulture),
                HostName = memEntry.HostName,
                Status = memEntry.Status.ToString(),
                ProxyPort = memEntry.ProxyPort.ToString(CultureInfo.InvariantCulture),

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