Fixed max age and down-sampling scoping to non-attached paths, downsampling range resolution, and add directory fill method setting

Author: ritchiecarroll

Source/Libraries/Adapters/openHistorian.Adapters/LocalOutputAdapter.cs

@@ -204,6 +204,7 @@
     <Compile Include="Snap\Filters\PointIdMatchFilterDefinition.cs" />
     <Compile Include="Snap\UnionTreeStreamSortHelper.cs" />
     <Compile Include="Snap\Services\ArchiveDetails.cs" />
+    <Compile Include="Snap\Services\ArchiveDirectoryFillMethod.cs" />
     <Compile Include="Snap\Services\ArchiveDirectoryMethod.cs" />
     <Compile Include="Snap\Services\ArchiveListEditor.cs" />
     <Compile Include="Snap\Services\ArchiveListSettings.cs" />

Source/Libraries/GSF.SortedTreeStore/GSF.SortedTreeStore.csproj

@@ -0,0 +1,44 @@
+//******************************************************************************************************
+//  ArchiveDirectoryFillMethod.cs - Gbtc
+//
+//  Copyright © 2026, Grid Protection Alliance.  All Rights Reserved.
+//
+//  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See
+//  the NOTICE file distributed with this work for additional information regarding copyright ownership.
+//  The GPA licenses this file to you under the MIT License (MIT), the "License"; you may
+//  not use this file except in compliance with the License. You may obtain a copy of the License at:
+//
+//      http://opensource.org/licenses/MIT
+//
+//  Unless agreed to in writing, the subject software distributed under the License is distributed on an
+//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the
+//  License for the specific language governing permissions and limitations.
+//
+//  Code Modification History:
+//  ----------------------------------------------------------------------------------------------------
+//  06/23/2026 - J. Ritchie Carroll
+//       Generated original version of source code.
+//
+//******************************************************************************************************
+
+namespace GSF.Snap.Services
+{
+    /// <summary>
+    /// Specifies how a write directory is selected from the set of configured archive directories when more than one
+    /// is available.
+    /// </summary>
+    public enum ArchiveDirectoryFillMethod
+    {
+        /// <summary>
+        /// Fill each configured write path, in order, advancing to the next only when the current path's drive lacks
+        /// sufficient free space. This is the default and matches the historical archive write behavior.
+        /// </summary>
+        Sequential,
+
+        /// <summary>
+        /// Distribute new files across the configured write paths in round-robin order, skipping any path whose drive
+        /// lacks sufficient free space.
+        /// </summary>
+        RoundRobin
+    }
+}

Source/Libraries/GSF.SortedTreeStore/Snap/Services/ArchiveDirectoryFillMethod.cs

@@ -66,6 +66,7 @@ public AdvancedServerDatabaseConfig(string databaseName, string mainPath, bool s
             DesiredRemainingSpace =  5L * SI2.Giga;
             StagingCount = 3;
             DirectoryMethod = ArchiveDirectoryMethod.TopDirectoryOnly;
+            FillMethod = ArchiveDirectoryFillMethod.Sequential;
             DiskFlushInterval = 10000;
             CacheFlushInterval = 100;
         }
@@ -76,6 +77,12 @@ public AdvancedServerDatabaseConfig(string databaseName, string mainPath, bool s
         /// </summary>
         public ArchiveDirectoryMethod DirectoryMethod { get; set; }
 
+        /// <summary>
+        /// Gets or sets how a write path is selected from the final write paths when more than one is configured.
+        /// Defaults to <see cref="ArchiveDirectoryFillMethod.Sequential"/>.
+        /// </summary>
+        public ArchiveDirectoryFillMethod FillMethod { get; set; }
+
         /// <summary>
         /// The name associated with the database.
         /// </summary>
@@ -126,7 +133,7 @@ public string FinalFileExtension
         public bool ImportAttachedPathsAtStartup { get; set; }
 
         /// <summary>
-        /// Gets all of the paths that are known by this historian.
+        /// Gets all paths that are known by this historian.
         /// A path can be a file name or a folder.
         /// </summary>
         public List<string> ImportPaths { get; }
@@ -160,7 +167,7 @@ public string FinalFileExtension
         public int DiskFlushInterval { get; set; }
 
         /// <summary>
-        /// The number of milliseconds before data is taken from it's cache and put in the
+        /// The number of milliseconds before data is taken from its cache and put in the
         /// memory file.
         /// </summary>
         /// <remarks>
@@ -238,10 +245,12 @@ private void ToWriteProcessorSettings(WriteProcessorSettings settings)
                 }
                 else
                 {
-                    // Final staging file
+                    // Final staging file - this is the only stage that writes across the configured final paths, so the
+                    // fill method (sequential vs round-robin) applies here
                     rollover.ArchiveSettings.ConfigureOnDisk(finalPaths, DesiredRemainingSpace,
                         DirectoryMethod, ArchiveEncodingMethod, DatabaseName.ToNonNullNorEmptyString("stage" + stage).RemoveInvalidFileNameCharacters(),
                         finalFilePendingExtension, finalFileFinalExtension, FileFlags.GetStage(stage));
+                    rollover.ArchiveSettings.FillMethod = FillMethod;
                 }
 
                 rollover.LogPath = m_mainPath;

Source/Libraries/GSF.SortedTreeStore/Snap/Services/Configuration/AdvancedServerDatabaseConfig.cs

@@ -25,6 +25,8 @@
 using System;
 using System.IO;
 using System.Linq;
+using System.Threading;
+using GSF.Immutable;
 using GSF.IO;
 using GSF.Snap.Storage;
 using GSF.Snap.Types;
@@ -41,6 +43,7 @@ public class SimplifiedArchiveInitializer<TKey, TValue>
     {
         private SimplifiedArchiveInitializerSettings m_settings;
         private readonly ReaderWriterLockEasy m_lock;
+        private int m_writePathSeed;
 
         /// <summary>
         /// Creates a <see cref="ArchiveInitializer{TKey,TValue}"/>
@@ -74,7 +77,7 @@ public void UpdateSettings(SimplifiedArchiveInitializerSettings settings)
 
         /// <summary>
         /// Creates a new <see cref="SortedTreeTable{TKey,TValue}"/> based on the settings passed to this class.
-        /// Once created, it is up to he caller to make sure that this class is properly disposed of.
+        /// Once created, it is up to the caller to make sure that this class is properly disposed of.
         /// </summary>
         /// <param name="startKey">the first key in the archive file</param>
         /// <param name="endKey">the last key in the archive file</param>
@@ -100,7 +103,7 @@ public SortedTreeTable<TKey, TValue> CreateArchiveFile(TKey startKey, TKey endKe
         private string CreateArchiveName(string path)
         {
             path = GetPath(path, DateTime.Now);
-            return Path.Combine(path, m_settings.Prefix.ToLower() + "-" + Guid.NewGuid() + "-" + DateTime.UtcNow.Ticks + m_settings.PendingExtension);
+            return Path.Combine(path, $"{m_settings.Prefix.ToLower()}-{Guid.NewGuid()}-{DateTime.UtcNow.Ticks}{m_settings.PendingExtension}");
         }
 
         /// <summary>
@@ -119,7 +122,7 @@ private string CreateArchiveName(string path, TKey startKey, TKey endKey)
                 return CreateArchiveName(path);
 
             path = GetPath(path, startDate);
-            return Path.Combine(path, m_settings.Prefix.ToLower() + "-" + startDate.ToString("yyyy-MM-dd HH.mm.ss.fff") + "_to_" + endDate.ToString("yyyy-MM-dd HH.mm.ss.fff") + "-" + DateTime.UtcNow.Ticks + m_settings.PendingExtension);
+            return Path.Combine(path, $"{m_settings.Prefix.ToLower()}-{startDate:yyyy-MM-dd HH.mm.ss.fff}_to_{endDate:yyyy-MM-dd HH.mm.ss.fff}-{DateTime.UtcNow.Ticks}{m_settings.PendingExtension}");
         }
 
         private string GetPath(string rootPath, DateTime time)
@@ -135,25 +138,45 @@ private string GetPath(string rootPath, DateTime time)
                     rootPath = Path.Combine(rootPath, time.Year.ToString() + time.Month.ToString("00"));
                     break;
                 case ArchiveDirectoryMethod.YearThenMonth:
-                    rootPath = Path.Combine(rootPath, time.Year.ToString() + '\\' + time.Month.ToString("00"));
+                    rootPath = Path.Combine(rootPath, $"{time.Year}\\{time.Month:00}");
                     break;
             }
+
             if (!Directory.Exists(rootPath))
                 Directory.CreateDirectory(rootPath);
+            
             return rootPath;
         }
 
+        // Selects a write path with enough free space using the configured fill method. Sequential fill always starts
+        // at the first path (filling each in order); round-robin rotates the starting candidate via a per-instance
+        // interlocked seed so new files are distributed across the configured write paths.
         private string GetPathWithEnoughSpace(long estimatedSize)
         {
+            ImmutableList<string> paths = m_settings.WritePath;
+            int count = paths.Count;
+
+            int start = m_settings.FillMethod == ArchiveDirectoryFillMethod.RoundRobin ? 
+                ((Interlocked.Increment(ref m_writePathSeed) - 1) % count + count) % count : 0;
+
+            // No size estimate: return the selected path without a free-space check
             if (estimatedSize < 0)
-                return m_settings.WritePath.First();
+                return paths[start];
+
             long remainingSpace = m_settings.DesiredRemainingSpace;
-            foreach (string path in m_settings.WritePath)
+
+            // Scan all candidate paths once, beginning at the selected position and wrapping around, returning the
+            // first whose drive has enough free space to store the estimated file while leaving the desired remaining space
+            for (int offset = 0; offset < count; offset++)
             {
+                string path = paths[(start + offset) % count];
+
                 FilePath.GetAvailableFreeSpace(path, out long freeSpace, out _);
+
                 if (freeSpace - estimatedSize > remainingSpace)
                     return path;
             }
+
             throw new Exception("Out of free space");
         }
 

Source/Libraries/GSF.SortedTreeStore/Snap/Services/Writer/SimplifiedArchiveInitializer'2.cs

@@ -38,6 +38,7 @@ public class SimplifiedArchiveInitializerSettings
         : SettingsBase<SimplifiedArchiveInitializerSettings>
     {
         private ArchiveDirectoryMethod m_directoryMethod;
+        private ArchiveDirectoryFillMethod m_fillMethod;
         private string m_prefix;
         private string m_pendingExtension;
         private string m_finalExtension;
@@ -57,6 +58,7 @@ public SimplifiedArchiveInitializerSettings()
         private void Initialize()
         {
             m_directoryMethod = ArchiveDirectoryMethod.TopDirectoryOnly;
+            m_fillMethod = ArchiveDirectoryFillMethod.Sequential;
             m_prefix = string.Empty;
             m_pendingExtension = ".~d2i";
             m_finalExtension = ".d2i";
@@ -83,6 +85,20 @@ public ArchiveDirectoryMethod DirectoryMethod
             }
         }
 
+        /// <summary>
+        /// Gets or sets the method used to select a write path when more than one is configured. Defaults to
+        /// <see cref="ArchiveDirectoryFillMethod.Sequential"/>.
+        /// </summary>
+        public ArchiveDirectoryFillMethod FillMethod
+        {
+            get => m_fillMethod;
+            set
+            {
+                TestForEditable();
+                m_fillMethod = value;
+            }
+        }
+
         /// <summary>
         /// Gets/Sets the file prefix. Can be String.Empty for no prefix.
         /// </summary>
@@ -92,13 +108,16 @@ public string Prefix
             set
             {
                 TestForEditable();
+                
                 if (string.IsNullOrWhiteSpace(value))
                 {
                     m_prefix = string.Empty;
                     return;
                 }
+                
                 if (value.IndexOfAny(Path.GetInvalidFileNameChars()) >= 0)
-                    throw new ArgumentException("filename has invalid characters.", "value");
+                    throw new ArgumentException("filename has invalid characters.", nameof(value));
+                
                 m_prefix = value;
             }
         }
@@ -149,9 +168,7 @@ public EncodingDefinition EncodingMethod
             set
             {
                 TestForEditable();
-                if (value is null)
-                    throw new ArgumentNullException("value");
-                m_encodingMethod = value;
+                m_encodingMethod = value ?? throw new ArgumentNullException(nameof(value));
             }
         }
 
@@ -168,18 +185,13 @@ public long DesiredRemainingSpace
             set
             {
                 TestForEditable();
+
                 if (value < 100 * 1024L * 1024L)
-                {
                     m_desiredRemainingSpace = 100 * 1024L * 1024L;
-                }
                 else if (value > 1024 * 1024L * 1024L * 1024L)
-                {
                     m_desiredRemainingSpace = 1024 * 1024L * 1024L * 1024L;
-                }
                 else
-                {
                     m_desiredRemainingSpace = value;
-                }
             }
         }
 
@@ -212,8 +224,9 @@ public void ConfigureOnDisk(IEnumerable<string> paths, long desiredRemainingSpac
 
         public override void Save(Stream stream)
         {
-            stream.Write((byte)1);
+            stream.Write((byte)2);
             stream.Write((int)m_directoryMethod);
+            stream.Write((int)m_fillMethod);
             stream.Write(m_prefix);
             stream.Write(m_pendingExtension);
             stream.Write(m_finalExtension);
@@ -238,21 +251,30 @@ public override void Load(Stream stream)
             switch (version)
             {
                 case 1:
+                case 2:
                     m_directoryMethod = (ArchiveDirectoryMethod)stream.ReadInt32();
+
+                    // Fill method was introduced in version 2; version 1 streams default to Sequential
+                    m_fillMethod = version >= 2 ? (ArchiveDirectoryFillMethod)stream.ReadInt32() : ArchiveDirectoryFillMethod.Sequential;
+
                     m_prefix = stream.ReadString();
                     m_pendingExtension = stream.ReadString();
                     m_finalExtension = stream.ReadString();
                     m_desiredRemainingSpace = stream.ReadInt64();
                     m_encodingMethod = new EncodingDefinition(stream);
+                    
                     int cnt = stream.ReadInt32();
                     m_writePath.Clear();
+                    
                     while (cnt > 0)
                     {
                         cnt--;
                         m_writePath.Add(stream.ReadString());
                     }
+                    
                     cnt = stream.ReadInt32();
                     m_flags.Clear();
+                    
                     while (cnt > 0)
                     {
                         cnt--;
@@ -270,6 +292,5 @@ public override void Validate()
             if (WritePath.Count == 0)
                 throw new Exception("Missing write paths.");
         }
-
     }
 }

Source/Libraries/GSF.SortedTreeStore/Snap/Services/Writer/SimplifiedArchiveInitializerSettings.cs

@@ -69,6 +69,15 @@ public ArchiveDirectoryMethod DirectoryMethod
             set => m_config.DirectoryMethod = value;
         }
 
+        /// <summary>
+        /// Specify how a write path is selected from the final archive directories when more than one is configured.
+        /// </summary>
+        public ArchiveDirectoryFillMethod FillMethod
+        {
+            get => m_config.FillMethod;
+            set => m_config.FillMethod = value;
+        }
+
         /// <summary>
         /// Gets or sets the desired size of the final stage archive files.
         /// </summary>
@@ -126,7 +135,7 @@ public int DiskFlushInterval
         }
 
         /// <summary>
-        /// The number of milliseconds before data is taken from it's cache and put in the
+        /// The number of milliseconds before data is taken from its cache and put in the
         /// memory file.
         /// </summary>
         /// <remarks>
@@ -181,7 +190,7 @@ public bool ImportAttachedPathsAtStartup
         }
 
         /// <summary>
-        /// Gets all of the paths that are known by this historian.
+        /// Gets all the paths that are known by this historian.
         /// A path can be a file name or a folder.
         /// </summary>
         public List<string> ImportPaths => m_config.ImportPaths;

Source/Libraries/openHistorian.Core/Net/HistorianServerDatabaseConfig.cs

@@ -5,6 +5,7 @@
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/Abbreviations/=MD/@EntryIndexedValue">MD</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/Abbreviations/=URL/@EntryIndexedValue">URL</s:String>
 	<s:Boolean x:Key="/Default/GrammarAndSpelling/GrammarChecking/Exceptions/=primary_0020install_0020location/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/GrammarAndSpelling/GrammarChecking/Exceptions/=round_0020robin/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=allusers/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=ALOG/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Ampq/@EntryIndexedValue">True</s:Boolean>