33:
233:
Automatic
Storage Management (ASM) simplifies administration of Oracle-related files by allowing the administrator to reference disk groups (rather than individual disks and files) which ASM manages. ASM extends the Oracle Managed Files (OMF) functionality that also includes striping and mirroring to
244:
The main components of ASM are disk groups, each of which comprise several physical disks controlled as a single unit. The physical disks are known as ASM disks, while the files that reside on the disks are known as ASM files. The locations and names for the files are controlled by ASM, but
284:
One can configure ASM diskgroups to have no redundancy (external), two-way mirroring (normal), or three-way mirroring (high). In the case of normal and high mirrors, good practice suggests having fail groups that talk to different controllers for performance and fail-safe reasons.
248:
The level of redundancy and the granularity of the striping can be controlled using templates. Oracle
Corporation provides default templates for each file-type stored by ASM, but additional templates can be defined as needed.
252:
Failure groups are defined within a disk group to support the required level of redundancy. For two-way mirroring, a disk group might contain two failure groups, in which case individual files are written to two locations.
303:
In the case of high redundancy, ASM does three-way mirroring, maintaining three copies of the data through software mirroring. When querying for mirror information, DBAs will see three mirrors in this case.
300:, ASM does two-way mirroring, meaning that ASM maintains two copies of the data through software mirroring. When querying for mirror information, DBAs will see two mirrors in this case.
234:
provide balanced and secure storage. DBAs can use the ASM functionality in combination with existing raw and cooked file-systems, along with OMF and manually managed files.
371:
Oracle ASM Dynamic Volume
Manager is the foundation for ASM Cluster File System (ACFS). ACFS is a general-purpose cluster file system and supports non-Oracle applications.
225:, ASM introduces two new ones - OSMB and RBAL. OSMB opens and creates disks in a diskgroup. RBAL provides the functionality of moving data between disks in a diskgroup.
407:
61:
241:
controls the ASM functionality. It isn't a full database instance, it provides just the memory structures, and as such is very small and lightweight.
358:
79:
386:
48:
207:
210:. The system then spreads these extents across all disks in a "diskgroup". One can think of a diskgroup in ASM as a
179:
333:
391:
313:
211:
132:
412:
297:
293:, but only stripes its files across all the disks that belong to the disk group that does external redundancy.
120:
203:
290:
183:
164:
DBAs can automate online redistribution of data, along with the addition and removal of disks/storage
43:
256:
Oracle ASM Dynamic Volume
Manager provides the foundation for the ASM Cluster File System (ACFS).
222:
116:
96:
245:
user-friendly aliases and directory structures can be defined by the DBA for ease of reference.
387:
http://twiki.cern.ch/twiki/pub/PSSGroup/Presentations2007/Inside_Oracle_ASM_LC_CERN_UKOUG07.ppt
354:
136:
17:
127:
statements in standard Oracle environments. Thus DBAs do not need extra skills in specific
54:
104:
100:
218:
159:
401:
155:
272:
enables management of database objects without specifying mount-points or filenames
214:
148:
348:
151:
128:
112:
111:
datafiles, control files and log files. To do so, it provides tools to manage
190:
175:
108:
394:: useful for users not familiar with SQL (one can write scripts with it)
353:. Oracle Press (2 ed.). McGraw Hill Professional (published 2011).
206:
out of datafiles, log-files, system files, control files and other
174:
Oracle supports third-party multipathing IO technologies (such as
168:
124:
26:
350:
Oracle
Database 11g Oracle Real Application Clusters Handbook
269:
provides near-optimal I/O balancing without any manual tuning
167:
the system maintains redundant copies and provides 3rd-party
107:(revision 1) onwards. ASM aims to simplify the management of
57:
a computer program guide or a vehicle for product promotion.
289:
In the case of external redundancy, ASM does not do any
259:
In summary, ASM provides the following functionality:
123:(DBAs) to control volumes and disks with familiar
266:manages disk redundancy within each disk group
8:
263:manages groups of disks, called disk groups
135:(which usually operate at the level of the
53:Needs to be pared down; Knowledge (XXG) is
80:Learn how and when to remove this message
408:Proprietary database management systems
325:
217:— with an ASM file corresponding to a
119:directly inside the database, allowing
347:Gopalakrishnan, K. (10 August 2011).
221:. In addition to the existing Oracle
7:
25:
334:"Database Administrator's Guide"
31:
95:(ASM) is a feature provided by
1:
93:Automatic Storage Management
18:Automatic storage management
51:. The specific problem is:
429:
47:to meet Knowledge (XXG)'s
314:Logical volume management
229:Implementation and usage
121:database administrators
296:In the case of normal
212:Logical Volume Manager
154:can take advantage of
198:Architecture overview
275:supports large files
223:background processes
62:improve this article
208:database structures
291:software mirroring
97:Oracle Corporation
90:
89:
82:
49:quality standards
40:This article may
16:(Redirected from
420:
374:
373:
368:
367:
344:
338:
337:
330:
137:operating system
85:
78:
74:
71:
65:
35:
34:
27:
21:
428:
427:
423:
422:
421:
419:
418:
417:
413:Oracle software
398:
397:
383:
378:
377:
365:
363:
361:
346:
345:
341:
332:
331:
327:
322:
310:
282:
231:
200:
145:
133:volume managers
101:Oracle Database
86:
75:
69:
66:
59:
36:
32:
23:
22:
15:
12:
11:
5:
426:
424:
416:
415:
410:
400:
399:
396:
395:
389:
382:
381:External links
379:
376:
375:
359:
339:
324:
323:
321:
318:
317:
316:
309:
306:
305:
304:
301:
294:
281:
278:
277:
276:
273:
270:
267:
264:
230:
227:
219:logical volume
199:
196:
195:
194:
187:
180:load balancing
172:
165:
162:
144:
141:
88:
87:
39:
37:
30:
24:
14:
13:
10:
9:
6:
4:
3:
2:
425:
414:
411:
409:
406:
405:
403:
393:
390:
388:
385:
384:
380:
372:
362:
360:9780071752626
356:
352:
351:
343:
340:
335:
329:
326:
319:
315:
312:
311:
307:
302:
299:
295:
292:
288:
287:
286:
279:
274:
271:
268:
265:
262:
261:
260:
257:
254:
250:
246:
242:
240:
235:
228:
226:
224:
220:
216:
213:
209:
205:
197:
192:
189:the need for
188:
185:
181:
177:
173:
171:functionality
170:
166:
163:
161:
158:and software
157:
156:data striping
153:
150:
147:
146:
142:
140:
138:
134:
130:
126:
122:
118:
114:
110:
106:
103:from release
102:
98:
94:
84:
81:
73:
63:
58:
56:
50:
46:
45:
38:
29:
28:
19:
370:
364:. Retrieved
349:
342:
328:
283:
258:
255:
251:
247:
243:
238:
236:
232:
215:volume group
202:ASM creates
201:
129:file systems
113:file systems
92:
91:
76:
67:
60:Please help
52:
41:
99:within the
64:if you can.
402:Categories
366:2015-01-05
320:References
298:redundancy
280:Redundancy
191:hot spares
105:Oracle 10g
70:March 2012
160:mirroring
308:See also
239:instance
193:diminish
176:failover
152:channels
143:Features
109:database
42:require
237:An ASM
204:extents
186:access)
117:volumes
44:cleanup
392:ASMCMD
357:
355:ISBN
169:RAID
115:and
184:SAN
182:to
178:or
139:).
131:or
125:SQL
55:not
404::
369:.
149:IO
336:.
83:)
77:(
72:)
68:(
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.