I have an Umbraco 7.3.4 site with a large number of nodes (20,000+).

The website takes forever to load and most of the time won't; the server RAM peaks around 3 GB, maxes out the CPU, and most of the time returns an error of: Failed to enter the lock within timeout.

Here are some items of interest in the log file:

_shutDownMessage=IIS configuration change
HostingEnvironment initiated shutdown
HostingEnvironment caused shutdown

_shutDownStack=   at System.Environment.GetStackTrace(Exception e, Boolean needFileInfo)
   at System.Environment.get_StackTrace()
   at System.Web.Hosting.HostingEnvironment.InitiateShutdownInternal()
   at System.Web.Hosting.HostingEnvironment.InitiateShutdownWithoutDemand()
   at System.Web.Hosting.PipelineRuntime.StopProcessing()

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 2016-05-16 10:52:23,223 [P4604/D12/T23] WARN  Umbraco.Core.Sync.DatabaseServerMessenger - No last synced Id found, this generally means this is a new server/install. The server will rebuild its caches and indexes and then adjust it's last synced id to the latest found in the database and will start maintaining cache updates based on that id

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 2016-05-16 10:52:23,237 [P4604/D12/T23] WARN  umbraco.content - Failed to load Xml, file does not exist.

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 2016-05-16 10:52:42,374 [P4604/D12/T8] INFO  umbraco.content - Save Xml to file...
 2016-05-16 10:52:45,666 [P4604/D12/T8] ERROR umbraco.content - Failed to save Xml to file.

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 2016-05-16 10:52:45,666 [P4604/D12/T8] ERROR umbraco.content - Failed to save Xml to file.
System.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.
   at System.Text.Encoding.GetBytes(String s)
   at umbraco.content.<SaveXmlToFileAsync>d__b.MoveNext()
 2016-05-16 10:53:00,501 [P4604/D12/T14] INFO  umbraco.content - Save Xml to file...
 2016-05-16 10:53:04,476 [P4604/D12/T14] ERROR umbraco.content - Failed to save Xml to file.
System.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.
   at System.Text.Encoding.GetBytes(String s)
   at umbraco.content.<SaveXmlToFileAsync>d__b.MoveNext()

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 2016-05-16 10:53:23,184 [P4604/D11/T24] ERROR UmbracoExamine.DataServices.UmbracoLogService - Provider=ExternalIndexer, NodeId=-1
System.Exception: Error indexing queue items,Lucene.Net.Store.AlreadyClosedException: this IndexWriter is closed
   at Lucene.Net.Index.IndexWriter.EnsureOpen(Boolean includePendingClose)
   at Lucene.Net.Index.IndexWriter.EnsureOpen()
   at Lucene.Net.Index.IndexWriter.UpdateDocument(Term term, Document doc)
   at Examine.LuceneEngine.Providers.LuceneIndexer.AddDocument(Dictionary`2 fields, IndexWriter writer, Int32 nodeId, String type) in x:\Projects\Examine\Examine\Projects\Examine\LuceneEngine\Providers\LuceneIndexer.cs:line 1322
   at Examine.LuceneEngine.Providers.LuceneIndexer.ProcessIndexQueueItem(IndexOperation op, IndexWriter writer) in x:\Projects\Examine\Examine\Projects\Examine\LuceneEngine\Providers\LuceneIndexer.cs:line 1802
   at Examine.LuceneEngine.Providers.LuceneIndexer.ProcessQueueItem(IndexOperation item, ICollection`1 indexedNodes, IndexWriter writer) in x:\Projects\Examine\Examine\Projects\Examine\LuceneEngine\Providers\LuceneIndexer.cs:line 1580
   at Examine.LuceneEngine.Providers.LuceneIndexer.ForceProcessQueueItems(Boolean block) in x:\Projects\Examine\Examine\Projects\Examine\LuceneEngine\Providers\LuceneIndexer.cs:line 1539, IndexSet: ExternalIndexSet
 2016-05-16 10:53:23,185 [P4604/D11/T24] ERROR UmbracoExamine.DataServices.UmbracoLogService - Provider=ExternalIndexer, NodeId=-1
System.Exception: Error indexing queue items,Lucene.Net.Store.AlreadyClosedException: this IndexWriter is closed
   at Lucene.Net.Index.IndexWriter.EnsureOpen(Boolean includePendingClose)
   at Lucene.Net.Index.IndexWriter.EnsureOpen()
   at Lucene.Net.Index.IndexWriter.Commit(IDictionary`2 commitUserData)

Is Umbraco not able to handle such a large amount of nodes without throwing a done of server resources at it?