A fix is available
APAR status
Closed as documentation error.
Error description
The Optimizing Performance guide shows the table that lists the general API client instrumentation categories, but there is no information about the virtual machines instrumentation trace categories. The following API categories are included in the instrumentation trace report (file named dsminstr.report.xxx), but are not documented in case of performance analysis of virtual machine backup using Tivoli Storage Manager client and Tivoli Data Protection for Virtual Environments. VM Snapshot - Represents time taken to generate and remove a VM guest snapshot with VMware using the VI SDK. - Some of this work is done asynchronously (for example: snapshot delete). VM Send Data - Represents time taken to send data to the Tivoli Storage Manager server. - Usually this activity is occurring in an interleaved fashion with the "VM I/O" reads from VMware to fill the buffer we will later send. - Each call is a buffer send to the Tivoli Storage Manager server. This category encapsulates the time for client-side dedup processing/encryption as well as the network send. - For FULL/IFFULL backups, the buffer is typically filled to 256 KB prior to send. With INCR/IFINCR backups, less data might be in the buffer. VM Get Data - Represents time taken to receive data from the Tivoli Storage Manager server. - This can involve fetching control files from the Tivoli Storage Manager server during incremental backup. - Can also involve buffer receives during VM guest restore which will later be written out using "VM I/O" writes to VMware. VM Query - Represents queries to the Tivoli Storage Manager server regarding certain options. - Queries conducted to determine if deduplication and/or compression are used. Also node filespace queries (for virtual machines). VM Query VE - Represents query made to VMware to determine changed disk areas (blocks) for VM guest disks. Uses the VMware VI SDK to determine a set of changed blocks. VM Assign - Represents Tivoli Storage Manager server group assignment using the dsmGroupHandler. VM VCM Lock - Represents semaphore locking which takes place during VCMLIB (Volume Control Manager) API calls. - Involves locking for volume control data reads/updates. Block control data manipulation, finding megablocks in a volume, etc. VM Transaction - Represents transaction processing conducted with the Tivoli Storage Manager server (start/end). VM I/O - Represents reading and writing activity done with VMware VM guest disks using the Vix Disk Library for VDDK disks. - This can involve any of the available transport paths (NBD, NBDSSL, SAN, HOTADD) used by the client. - Performance can vary depending on whether the disks being interacted with were thin or thick provisioned - also: whether they were/are lazy zeroed or not. - Reading from VMware disks over SAN has proved somewhat slower than direct reads from the disks using a raw volume I/O tool. - During VM guest backup, reads from VMware (<=256 KB each) are usually interleaved with sends to Tivoli Storage Manager from the same thread (no double-buffering yet in the code). - Represents time reading ctl file from local disk when sending it to the Tivoli Storage Manager server during backup. VM Control File I/O - Represents VM guest CTL file ("control file") I/O and interaction. - Writing control files during VM guest operations. Thread Wait - For Tivoli Storage Manager for VE clients, this has been found to represent the time it takes to open and close VDDK disks. - When you see this category, this means that this thread is waiting on the "utility thread" to open or close a VDDK (VM guest) disk. - With the Tivoli Storage Manager client during multi-session backup, there can be multiple threads which are backing up VM guests, but only 1 "utility thread" opening and closing guest disks. - This is a VMware limitation where the same thread that opens a disk has to close it. - In the General Availability code, disks are opened/closed one at a time by the utility thread, increasing the possibility of bottlenecks for a single client instance. - The utility thread opens/closes the disks via API calls to the VCenter/ESXi host. - The open/close time can also include the time taken to mount the disk on the client/proxy system. Tivoli Storage Manager Versions Affected: Tivoli Storage Manager client 6.4.x. and 7.1.x on all supported platforms Initial Impact: Low Additional Keywords: trace performances doc tuning vm vmware tdp tsm
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: * * All Tivoli Storage Manager server users. * **************************************************************** * PROBLEM DESCRIPTION: * * See error description. * **************************************************************** * RECOMMENDATION: * * None * ****************************************************************
Problem conclusion
Information about the Tivoli Storage Manager virtual machine instrumentation categories are available in Technote 1676872 at: http://www.ibm.com/support/docview.wss?uid=swg21676872 The same information will be added to the Tivoli Storage Manager Optimizing Performance Guide in the "Virtual machine instrumentation categories" topic. Affected platforms: AIX, HP-UX, Solaris, Linux, and Windows.
Temporary fix
Comments
APAR Information
APAR number
IT02526
Reported component name
TSM CLIENT
Reported component ID
5698ISMCL
Reported release
71W
Status
CLOSED DOC
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2014-06-13
Closed date
2014-07-16
Last modified date
2014-07-16
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Applicable component levels
[{"Line of Business":{"code":"LOB26","label":"Storage"},"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSGSG7","label":"Tivoli Storage Manager"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"71W"}]
Document Information
Modified date:
25 September 2021