Ugif 04 2011 storage prov-pot_march_2011

®

Storage Provisioning

Yoram BENCHETRIT – Advanced Problem Diagnostic Team
yoram.benchetrit@fr.ibm.com
© 2010 IBM Corporation

IBM Software Group | Information Management

Agenda

Feature Reference
Feature Administration API
Feature Setup
OAT interface
Lab Demo

IBM Confidential © 2010 IBM Corporation 2


Why Do We Need This Feature ?

A DBSA should have the ability to significantly
reduce the chance that their users will experience
“out-of-space” errors and the downtime associated
with these errors.



Storage Provisioning Quick Reference

Highly configurable, automatic expansion of dbspaces, temporary
dbspaces, sbspaces, temporary sbspaces and blobspaces
Chunks are extended and/or created as needed
IDS can also expand spaces before they are full
Feature is fully incorporated into OAT.
Feature was completed in PANTHER EVP 3
Feature is documented in:
– IBM Informix Administrator's Reference
– IBM Informix Administrator's Guide



Storage Provisioning – The Power of 2 !

Two available modes:
– Manual
– Automatic
Two available space expansion methods:
– Chunk extension
– Chunk creation
Two available interfaces:
– sysadmin task()/admin() functions (SQL interface)
– OAT (Graphical interface)



What is the Storage Pool ?

A list of raw devices, cooked files, and/or directories from which IDS
can allocate space as needed
For example:
Path: /dev/rawdevice1
Offset: 500000
Total Size: 2000000

Path: /ifmx/STORAGE_DIR
Offset: 0
Total Size: 0
storagepool table in the sysadmin database (sysadmin:storagepool)



Storage Pool Facts

There is one storage pool per IDS instance.
A file, device, or directory in the pool is called an entry.
You can add, modify, and delete storage pool entries.
Entries that are used up or found to be faulty are left in the pool, but
disabled.
IDS automatically detects and prevents potential chunk overlaps.
Extending a chunk does not use the pool.



Sysadmin Interface

There is new commands in the sysadmin task() function

– storagepool [ add | modify | delete | purge ]
– modify space [ sp_sizes | expand ]
– modify chunk [ extendable | extend ]
– create <object> from storagepool
– drop <object> to storagepool

• with <object> in dbspace, tempdbspace, sbspace, tempsbspace,
blobspace, chunk



Add an Entry in the Storage Pool

EXECUTE FUNCTION task("storagepool add",
"<path>",
"<offset>",
"<total_size>",
"<chunk_size>",
"<priority>");
Chunk Size
– Minimum size of a chunk created from this entry
The offset and sizes are in kilobytes by default, though other units
can be specified.
The priority is 1 (High), 2 (Medium), or 3 (Low).
W hen adding a directory to the storage pool, <offset> and
<total_size> must be specified as 0.


Modify a Pool Entry

Pool Entry can be modified using the 'entry_id' column stored in the
storagepool table in the sysadmin database (sysadmin:storagepool)

Pool Entry Modification
– EXECUTE FUNCTION task("storagepool modify",
"<entry_id>",
"<new_total_size>",
"<new_chunk_size>",
"<new_priority>");

Pool Entry Deletion
– EXECUTE FUNCTION task("storagepool delete",
"<entry_id>");


Expand a Space

EXECUTE FUNCTION task("modify space expand",
"<space_name>",
"<min_size>");

<space_name> can be a dbspace, tempdbspace sbspace,
tempsbspace, blobspace.

IDS will expand the space by either extending a chunk or adding a
chunk using the storage pool.

IDS might round the min_size up, depending on the space's page size
and any chosen pool entry's minimum chunk size.



Extend a Chunk

Chunks are not extendable by default. To make a chunk extendable:
– EXECUTE FUNCTION task("modify chunk extendable",
"<chunk_num>");

Now, you can extend it manually at any time:
– EXECUTE FUNCTION task("modify chunk extend",
"<chunk_num>",
"<min_size>");

You can also wait for the server to extend it automatically.

Certain chunks cannot be extended or made extendable:
– Blobspace and Smart Blobspace Chunks
– Mirrored chunks


Modify a Space

EXECUTE FUNCTION task("modify space sp_sizes",
"<space name>", "<create_size>", "<extend_size>");
Create Size
– Minimum size of a chunk automatically created in this space
Extend Size
– Minimum amount by which a chunk in this space can be
automatically extended
Neither setting affects manual operations.
Express as a percentage or a number of kilobytes.
Default values: 10% and 10000k, respectively



Create Object from the Storage Pool

The Storage pool can be used for more than just adding chunks to
existing spaces; it can also be used to create spaces from scratch.
Space Object
– EXECUTE FUNCTION task(
"create <object> from storagepool",
"<space_name>",
"<min_size>",
optional arguments...);
blobspace
Chunk Object
"create chunk from storagepool",
"<space_name>",
"<min_size>");


Drop Object to the Storage Pool

Dropped chunk space are automatically added to the Storage Pool.
Space Object
"drop <object> to storagepool",
"<space_name>");
blobspace
Chunk Object
"drop chunk to storagepool",
"<space_name>", "<path>", "<offset>");
The space or chunk object must be empty in order to be dropped.



New onstat -d flags

Flags Definition
– A : Auto-expand space
– E: Extendable chunk
$ onstat -d

Dbspaces

addressnumber flags fchunk nchunks pgsize flags owner name
45c77028 1 0x60001 1 1 2048 N BA informix rootdbs
45d9c570 2 0x60001 2 1 2048 N B informix datadbs

Chunk
address chunk/dbs offset size free bpages flags pathname
150da61c8 1 1 0 1050000 49717 PO-BE- /opt/chunks/rootchk



Chunk in Pool Directory

W hen a chunk is created from scratch using a directory entry in the
storage pool, its name takes the following format
– <server_name>_<space_name>_<p or m>_<counter>

Example
$ onstat -d

Chunk
address chunk/dbs offset size free bpages flags pathname
4c6fd018 2 3 0 100000 4864 PO-BE- /opt/chunks/pooldir/ids_datadbs_p_1



Storage Provisioning Setup

New ONCONFIG Parameters
– SP_AUTOEXPAND
– SP_THRESHOLD
– SP_W AITTIME
• Those parameter can be modified dynamically with onmode -w[mf]

Define the Storage Pool

Optionnaly, declare some existing chunks as extendable



Configuration Parameters

SP_AUTOEXPAND
– Use this parameter to toggle on or off the automatic expansion of
spaces.
– Affects both automatic chunk creations and automatic chunk
extensions
– Does not affect manual space creations or expansions
Examples:
SP_AUTOEXPAND 1 # Auto-expansion enabled
SP_AUTOEXPAND 0 # Auto-expansion disabled
Default value: 1 (automatic space expansion is enabled.)



Configuration Parameters (cont)

SP_THRESHOLD
– Minimum amount of free space allowed in a container, expressed as
a percentage or an absolute number of kilobytes.
– If the free kilobytes in a space fall below this threshold, the next
time the low-space-monitoring task runs, IDS will attempt to expand
the space.
– This setting applies to all spaces in the instance. You cannot
configure this for each dbspace.
– Settings between 50 and 1000 are invalid.
Examples:
SP_THRESHOLD 10 # Ten percent of total
SP_THRESHOLD 100000 # 100 Mb
Default value: 0


Configuration Parameters (Cont)

SP_WAITTIME
– The number of seconds that a thread will wait for space expansion
before returning an out-of-space error.

Examples:
– SP_WAITTIME 60 # Wait 1 minute, max
– SP_WAITTIME 0 # Don't wait at all

Default value: 30



Syadmin Sensor Monitoring

Proactive Allocation
– The syadmin sensor, 'mon_low_storage', will periodically monitor
existing storage spaces and automatically grow a container when its
free space falls below the configurable threshold.
– SP_THRESHOLD is set to 0 by default, hence this sensor is disabled
by default.
– The sensor runs every hour by default. This is a query to configure its
frequency :
DATABASE sysadmin;
UPDATE ph_task set tk_frequency = INTERVAL(<minutes>) MINUTE TO
MINUTE WHERE tk_name = “mon_low_storage”;



OAT Storage Administration

The Space Administration > Storage pages:

Combine the information displayed in the
Space Administration > Dbspaces and
Chunks pages.

Display information about tables, extents,
and the new storage pool.

Provide a central location for you to
administer storage space with OAT.



Storage > Server View
The server view displays summary information for storage spaces and usage on the server.

• Expand a panel for more information and actions.

• Use the tree to drill down on a particular space.



Storage > Server View > Spaces
The Spaces page displays information about the storage spaces on the server including:

• An indicator of whether the space is expandable.

• The create and extend sizes that are used when the space is expanded.

You can create a new space or expand, modify, or drop an existing space.



Storage > Create Space

You can create a space and configure it as expandable.

The option to show the SQL is provided for each storage action.



Storage > Expand Space
You can expand a space on demand.

• Basic option: Expand the space by the amount configured as the extend size.

• Advanced options: Specify the amount to expand the space by or to add a chunk.



Storage > Server View > Chunks

The Chunks page displays detailed information about the chunks on the server.

You can add or drop a chunk, modify a chunk to make it extendable, or extend a chunk.



Storage > Server View > Storage Pool

You can configure the database server to automatically expand storage space:

• The threshold sets the minimum space allowed before the space is expanded.

• The wait time sets how long threads wait for a new space to be added.

You can add, modify, and delete the storage pool entries.



Storage > Server View > Storage Pool

You can add a storage pool entry.



Storage > Space View
The space view displays information about the space selected in the tree including:

• Summary information and usage.

• Chunks, tables, and extents in the space.



Storage > Space View

Expand a panel for more information and actions.



Lab Demo

Lab 1
– Configuring and testing the automatic addition of space

Lab 2
– Configuring and testing various feature of storage provisioning


Ugif 04 2011 storage prov-pot_march_2011

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