ASM IOstats versus Rebalance & Striping
Hi,
We recently have set up a 2 node RAC with ASM.
The CRS and ASM are on 11.1.0.7
The database is on 10.2.0.4
All is on two AIX 5.3 TL10 nodes
We are kind of struggling to understand the striping of ASM. The two diskgroups DB01 & FB01 exist both of multiple disks. DB01 has 6 LUNs, FB01 has three.
These LUNs are virtual disks, assigned/configured by the VIO server of the systems and are logical disks somewhere on our SAN
Using the ASM diskgroups now we see that some disks are used more than others, and especially that some disks have a more worse average access-time than others.
Can anyone explain me if the below output tells me some of the disks behave better than others.
Does anyone of you guru's have a similar system with comparable stats on the disks?
(Unfortunately I can't format the out more readable)
Out ASM_POWER_LIMIT is set to three (3)
select inst_id, group_number gn, disk_number dn ,
2 writes, write_time, write_time/writes avg_write_time
3 from GV$ASM_DISK_IOSTAT order by inst_id, group_number, disk_number;
INST_ID GN DN WRITES WRITE_TIME AVG_WRITE_TIME
1 1 0 319 .000029 .000000090909
1 1 1 334 .000242 .000000724551
1 1 2 2,531 .000392 .000000154879
1 1 3 2,579 .000397 .000000153936
1 1 4 328 .000219 .000000667683
1 1 5 398 .000039 .000000097990
1 2 0 2,351 .000477 .000000202892
1 2 1 42 .000111 *.000002642857*
1 2 2 51 .000112 *.000002196078*
2 1 0 8,728 .003417 .000000391499
2 1 1 4,728 .001547 .000000327200
2 1 2 157,582 .030946 .000000196380
2 1 3 149,422 .030384 .000000203344
2 1 4 6,427 .002109 .000000328147
2 1 5 9,567 .002872 .000000300199
2 2 0 145,576 .029803 .000000204725
2 2 1 1,450 .001023 .000000705517
2 2 2 4,820 .002475 *.000000513485*
The output (tried to format it, but no luck ):
INSTNAME |GN |DN |READS |WRITES |RERRS |WERRS |BYTES_READ |BYTES_WRITTEN |READ_TIME/READS |WRITE_TIME/WRITES
WCSPRD1 |1 |0 |40,984 |2,559 |0 |0 |740,172,288 |19,907,072 |.000000143690 |.000000120750
WCSPRD1 |1 |1 |2,245 |2,039 |0 |0 |89,171,456 |20,096,000 |.000000864588 |.000000377146
WCSPRD1 |1 |2 |72,980 |36,721 |0 |0 |1,223,776,768 |584,610,816 |.000000119636 |.000000221780
WCSPRD1 |1 |3 |7,296 |35,942 |0 |0 |124,814,336 |579,739,648 |.000000144874 |.000000222136
WCSPRD1 |1 |4 |170,136|2,048 |0 |0 |2,858,811,392 |16,337,920 |.000000061316 |.000000474121
WCSPRD1 |1 |5 |2,020 |4,768 |0 |0 |138,240,000 |35,438,592 |.000001297030 |.000000097525
WCSPRD1 |2 |0 |6,453 |34,147 |0 |0 |106,086,400 |577,748,992 |.000000091430 |.000000230855
WCSPRD1 |2 |1 |4 |42 |0 |0 |360,448 |18,938,880 |.000000250000 |.000002642857
WCSPRD1 |2 |2 |2 |51 |0 |0 |262,144 |19,120,128 |.000001500000 |.000002196078
WCSPRD2 |1 |0 |255,702|12,493 |0 |0 |5,329,231,872 |369,942,528 |.000000203569 |.000000584807
WCSPRD2 |1 |1 |77,829 |8,913 |0 |0 |2,363,526,656 |303,967,232 |.000000556464 |.000000723999
WCSPRD2 |1 |2 |445,364|196,013|0 |0 |8,289,651,200 |3,264,385,024 |.000000279183 |.000000233699
WCSPRD2 |1 |3 |103,254|185,410|0 |0 |2,685,607,936 |3,189,159,936 |.000000249007 |.000000230128
WCSPRD2 |1 |4 |972,911|11,013 |0 |0 |17,041,897,984 |307,239,424 |.000000090843 |.000000679833
WCSPRD2 |1 |5 |73,327 |13,987 |0 |0 |2,422,184,960 |379,976,704 |.000001152986 |.000000622721
WCSPRD2 |2 |0 |34,462 |177,479|0 |0 |564,985,856 |3,012,513,792 |.000000069265 |.000000215755
WCSPRD2 |2 |1 |4 |1,530 |0 |0 |360,448 |127,465,984 |.000000500000 |.000000892157
WCSPRD2 |2 |2 |2 |4,973 |0 |0 |262,144 |183,618,048 |.000002000000 |.000000577720
Edit: There is 'No Imbalance' in the diskgroups according to the queries.
Similar Messages
-
ASM shows abnormal I/O response time
Hi,
We have a two node RAC on AIX 5.3-TL10 running Oracle 11.1.0.7
We have had a huge I/O problem today, with the storage on ASM
The ASM instance consists of 9 x 16Gb disks for Data diskgroup and 3x16Gb for Recovery Area diskgroup.
Both diskgroups use external redundancy.
All disks are on SAN storage
Now the question:
We see in the disk stats the following:
INSTNAME GN DN READS WRITES RERRS WERRS BYTES_READ BYTES_WRITTEN READ_TIME/READS WRITE_TIME/WRITES
WCSPRD2 1 0 4,471,632 1,067,564 0 0 165,201,409,536 30,609,315,328 .061899937552 <== .057094084241
WCSPRD2 1 1 4,531,860 1,196,263 0 0 164,387,738,112 32,506,625,536 .029503535890 .053256503317
WCSPRD2 1 2 4,559,730 1,163,303 0 0 164,523,316,224 31,543,020,544 .022800459600 .045446761477
WCSPRD2 1 3 4,585,842 1,178,201 0 0 164,725,525,504 32,636,038,144 .064802255800 <== .057945133663
WCSPRD2 1 4 6,405,113 1,159,063 0 0 195,604,026,368 32,158,811,136 .022066317789 .052220315111
WCSPRD2 1 5 5,322,150 1,127,490 0 0 175,831,556,608 31,319,253,504 .020443702659 .042821491187
WCSPRD2 1 6 4,464,782 1,074,408 0 0 155,865,391,104 28,310,427,136 .031281829331 .049956605704
WCSPRD2 1 7 4,456,535 972,670 0 0 158,696,644,608 26,818,985,984 .031853965462 .048030197598
WCSPRD2 1 8 5,599,789 1,195,371 0 0 172,564,756,480 28,008,355,840 .024652429429 .042036854716
WCSPRD2 2 0 135,027 1,667,660 0 0 2,198,231,552 86,954,245,120 .001943523036 .019420785309
WCSPRD2 2 1 1,811 1,340,450 0 0 1,285,632 81,578,938,880 .008952528437 .020978272570
WCSPRD2 2 2 910 1,340,922 0 0 727,040 81,626,418,688 .003186924176 .016962261022Can anyone of you guru's explain the abnormal average readtimes for DN 0 and 3 in GN 1, being 61.8 and 64.8 ms versus an average of around 25ms of the other disks.
Any input is appreciated.
Thanks
Frank-JanHi,
Here they are:
Tablespace IO Stats DB/Inst: WCSPRD/WCSPRD2 Snaps: 4737-4738
-> ordered by IOs (Reads + Writes) desc
Tablespace
Av Av Av Av Buffer Av Buf
Reads Reads/s Rd(ms) Blks/Rd Writes Writes/s Waits Wt(ms)
WCTBLSPC
275,855 77 116.1 1.5 26,064 7 3,183 217.4
SYSAUX
2,127 1 141.3 1.3 911 0 0 0.0
TEMP
1,194 0 23.7 7.2 941 0 0 0.0
SYSTEM
2,002 1 230.3 1.8 127 0 0 0.0
UNDOTBS2
5 0 8.0 1.0 1,499 0 16 141.9
UNDOTBS1
3 0 6.7 1.0 1 0 83 1.6
USERS
1 0 140.0 1.0 1 0 0 0.0
WCS_KRG
1 0 0.0 1.0 1 0 0 0.0
File IO Stats DB/Inst: WCSPRD/WCSPRD2 Snaps: 4737-4738
-> ordered by Tablespace, File
Tablespace Filename
Av Av Av Av Buffer Av Buf
Reads Reads/s Rd(ms) Blks/Rd Writes Writes/s Waits Wt(ms)
SYSAUX +DB01/wcsprd/datafile/sysaux.338.715000059
2,127 1 141.3 1.3 911 0 0 0.0
SYSTEM +DB01/wcsprd/datafile/system.1070.715000059
2,002 1 230.3 1.8 127 0 0 0.0
TEMP +DB01/wcsprd/tempfile/temp.1073.715000187
1,194 0 23.7 7.2 941 0 0 N/A
UNDOTBS1 +DB01/wcsprd/datafile/undotbs1.1072.715000061
3 0 6.7 1.0 1 0 83 1.6
UNDOTBS2 +DB01/wcsprd/datafile/undotbs2.1067.715000389
5 0 8.0 1.0 1,499 0 16 141.9
USERS +DB01/wcsprd/datafile/users.257.715000061
1 0 140.0 1.0 1 0 0 0.0
WCS_KRG +DB01/wcsprd/datafile/wcs_krg.1058.715087247
1 0 0.0 1.0 1 0 0 0.0
WCTBLSPC +DB01/wcsprd/datafile/wctblspc.1052.715780877
75,215 21 126.1 1.5 6,476 2 554 77.2
WCTBLSPC +DB01/wcsprd/datafile/wctblspc.1053.715856291
67,247 19 112.5 1.5 5,989 2 680 363.7
WCTBLSPC +DB01/wcsprd/datafile/wctblspc.1054.715856293
62,907 18 104.6 1.6 7,417 2 706 161.2
WCTBLSPC +DB01/wcsprd/datafile/wctblspc.1057.715087269
70,486 20 119.1 1.3 6,182 2 1,243 231.8I can't see anything special here. The WCTBLSPC contains our Webshop data, and is accessed most frequently.
What bothers me is that ASM data should be striped.
If that would be completely true, then why are especially two disks very busy. It looks as is these two disks contain the most recent data of the Tablespace and striping is not completely spread across all 9 disks
I'm very curious for your findings.
Thanks
FJFranken -
* This was posted in the "Installation" Thread, but I copied it here to see if I can get more responses, Thank you.*
Hello,
I am about to set up a new Oracle 10.2 Database server. In the past, I used RAID5 since 1) it was a fairly small database 2) there were not alot of writes 3) high availability 4) wasted less space compared to other RAID techniques.
However, even though our database is still small (around 100GB), we are noticing that when we update our data, the time it takes is starting to grow to a point whereby the update that used to take about an hour, now takes 10-12 hours or more. One thing we noticed that if we created another tablespace which had a block size of 16KB versus our normal tablespace which had a block size of 8KB, we almost cut the update time in half.
So, we decided that we should really start from scratch on a new server and tune it optimally. Here are some questions I have:
1) Our server is a DELL PowerEdge 2850 with 4x146GB Hard Drives (584GB total). What is the best way to set up the disks? Should I use RAID 1+0 for everything? Should I use ASM? If I use ASM, how is the RAID configured? Do I use RAID0 for ASM since ASM handles mirroring and striping? How should I setup the directory structure? How about partitioning?
2) I am installing this on Linux and when I tried on my old system to use 32K block size, it said I could only use 16K due to my OS. Is there a way to use a 32K block size with Linux? Should I use a 32K block size?
Thanks!Hi
RAID 0 does indeed offer best performance, however if any one drive of the striped set fails you will lose all your data. If you have not considered a backup strategy now would be the time to do so. For redundancy RAID 1 Mirror might be a better option as this will offer a safety net in case of a single drive failure. A RAID is not a backup and you should always consider a workable backup strategy.
Purchase another 2x1TB drives and you could consider a RAID 10? Two Stripes mirrored.
Not all your files will be large ones as I'm guessing you'll be using this workstation for the usual mundane matters such as email etc? Selecting a larger block size with small file sizes usually decreases performance. You have to consider all applications and file sizes, in which case the best block size would be 32k.
My 2p
Tony -
Install Recommendations (RAID, ASM, Block Size etc)
Hello,
I am about to set up a new Oracle 10.2 Database server. In the past, I used RAID5 since 1) it was a fairly small database 2) there were not alot of writes 3) high availability 4) wasted less space compared to other RAID techniques.
However, even though our database is still small (around 100GB), we are noticing that when we update our data, the time it takes is starting to grow to a point whereby the update that used to take about an hour, now takes 10-12 hours or more. One thing we noticed that if we created another tablespace which had a block size of 16KB versus our normal tablespace which had a block size of 8KB, we almost cut the update time in half.
So, we decided that we should really start from scratch on a new server and tune it optimally. Here are some questions I have:
1) Our server is a DELL PowerEdge 2850 with 4x146GB Hard Drives (584GB total). What is the best way to set up the disks? Should I use RAID 1+0 for everything? Should I use ASM? If I use ASM, how is the RAID configured? Do I use RAID0 for ASM since ASM handles mirroring and striping? How should I setup the directory structure? How about partitioning?
2) I am installing this on Linux and when I tried on my old system to use 32K block size, it said I could only use 16K due to my OS. Is there a way to use a 32K block size with Linux? Should I use a 32K block size?
Thanks!The way I usually handle databases of that size if you don't feel like migrating to ASM redundancy is to use RAID-10. RAID5 is HORRIBLY slow (your redo logs will hate you) and if your controller is any good, a RAID-10 will be the same speed as a RAID-0 on reads, and almost as fast on writes. Also, when you create your array, make the stripe blocks as close to 1MB as you can. Modern disks can usually cache 1MB pretty easily, and that will speed the performance of your array by a lot.
I just never got into ASM, not sure why. But I'd say build your array as a RAID-10 (you have the capacity) and you'll notice a huge difference.
16k block size should be good enough. If you have recordsets that are that large, you might want to consider tweaking your multiblock read count.
~Jer -
Hi,
Was going through Oracle ASM document and came across this topic, need some clarification on this please.
"The disks are first taken offline and then automatically dropped. In this case, the disk group remains mounted and serviceable. In addition, because of mirroring, all of the disk group data remains accessible. After the disk drop operation, Oracle ASM performs a rebalance to restore full redundancy for the data on the failed disks". -- What does this mean?
ThanksSimple example.
Single normal redundancy diskgroup DATA1 with 2 failgroups called MIRROR1 and MIRROR2. Each failgroup has 3 x disks (let's say 512GB).
Disk 2 in failgroup MIRROR1 fails. The MIRROR1 failgroup is not available as a result. DB operations continue unaware of the problem as MIRROR2 is online and working fine.
The dba cannot fix disk 2 within the meantime for repair period of ASM. ASM forces disk 2 out the MIRROR1 failgroup by force dropping it. MIRROR1 has now 2 disk remaining.
ASM starts a rebalance process to stripe the contents of the MIRROR1 failgroup across 2 disks - as oppose to 3 disks. If the space in use fits on 2 disks the rebalance operation will succeed. MIRROR1 will become online and available. But it will only be able to carry 1TB of data, as oppose to MIRROR2 with it 3 disks and 1.5TB capacity.
If the space used cannot be striped across the remaining disks in MIRROR1, the rebalance will fail due to insufficient capacity and the failgroup will remain offline.
In either scenario, the recommended action is to add a new 512GB disk to MIRROR1, reverting it back to a 3 disk failgroup, and then rebalance the failgroup. -
Dear All,
Here is the configuration we have:
Primary Database: Oracle RAC (2 Nodes). 11g R1 RAC, 10g R2 Database using ASM (OS: Windows Server 2003)
Data Guard: 10g R2 Database using ASM (OS: Windows Server 2003)
We are getting the following errors in the alert log file of ASM Instance (Data Guard) - Data Gaurd mode is 'Max Performance':
ORA-00270: error creating archive log +DG_DATAFILES_AND_FB/accelastdby/primary_arch_logs/arc32471_0721252017.002
ORA-19504: failed to create file "+DG_DATAFILES_AND_FB/accelastdby/primary_arch_logs/arc32471_0721252017.002"
ORA-17502: ksfdcre:4 Failed to create file +DG_DATAFILES_AND_FB/accelastdby/primary_arch_logs/arc32471_0721252017.002
ORA-15041: diskgroup space exhausted
Uopn checking the disk group DG_DATAFILES_AND_FB, free space is 0.
What are the possible options to create more space on this disk group? Can we delete some files safely without any impact (for example: Archive logs which have been applied to database)?
Thanks for your advice.
Regards,
Muhammad RiazHi,
First you can add more disks to the diskgroup so you can get more space, ASM will do rebalance once new disks added.
Second, It seems that your archivelog in dataguard were not deleted after being applied. You can delete the applied archivelog in dataguard, use RMAN is the best option
Hope this helps
Cheers
FZheng -
Hi all,
from performance perspective: Which RAID levels are recommended to store OCR/Voting disks , Redo logs, Control files, datafiles in an 11gR2 RAC using ASM?
- OCR/Voting disks with NORNAL redundancy ASM level.
- Redo logs, Control files, datafiles, temp files EXTERNAL redundancy ASM level.
(we will use Redhat Enterprise Linux 5.5)
Thank you,
DiegoDiego wrote:
from performance perspective: Which RAID levels are recommended to store OCR/Voting disks , Redo logs, Control files, datafiles in an 11gR2 RAC using ASM?A 2-way mirror with a quorum disk is needed for the OCR and voting disk. This mean at minimum 3 disks.
For the database - that depends entirely on what redundancy you need for the database layer.
ASM automatically stripes across the disks for a diskgroup. You can then choose to mirror that in addition. Or you can use external mirroring (on the storage server/SAN). Or you can use RAID10 on the SAN and then use single stiped and mirrored LUNs per diskgroup. Or you can use multiple such LUNs per diskgroup, which means ASM will stripe the striped set. Not a real issue and covered in an Oracle support note.
As ASM does not support RAID5/6/7, you can use that on the physical storage layer and then simply stripe in ASM.
Or you can use 2 storage servers and use ASM to stripe the disks (in a diskgroup) per server. Then mirror these across storage server boundaries, thus introducing redundancy at physical storage server layer.
Lots of possibilities and combinations. The best being whatever meets your requirements the best.
Also keep in mind that the fabric layer also need to be redundant. No use of having 2 storage servers for example and mirroring across these for redundancy, when connectivity to the storage servers are via a single non-redundant fabric layer switch. Or wiring a dual port HBA/HCA into the same switch (cable failure covered, but loose the switch and loose all connectivity to the fabric layer), -
We want to use ASM. The SUN STORAGE has RAID. Unfortunately the statements about the combination of ASM with STORAGE systems of Oracle are not clear. In principle I have two possibilities:
1. Using ASM with mirroring and striping without RAID.
2. Using ASM only with striping and RAID (10, 5).
What I do not understand, RAID accomplishes striping and ASM also. So the striping will be done 2 times. That cannot be good? If nevertheless, are ASM and RAID(10, 5) rather the choice or ASM without RAID?
Thank you in advance,
Michaelare ASM and RAID(10, 5) rather the choice or ASM without RAID? Check this thread ASM vs RAID5/RAID10
-
Hi All,
The ASM defaultly use the striping method, now i want to use the Mirroing also, now can i do that, and what is the minimum requirement for that.
Regards
S.Senthil KumarYou can do mirroring by defining FAILURE GROUPS in diskgroups and the minimum requirement is more than 1 disk. Read the oracle doc for more on failure groups.
Daljit Singh -
Move disk devices between diskgroup in ASM SAN
Hi Experts,
We have a 4 nodes oracle 11.1 RAC with 10.2.04 database at red hat 5.1 Linux
there are two diskgroup to support database. data1 and data2.
data1 is for data files as 500G and data2 is for FRA as 1.7T.
in the back, 4 candidate disks to support data1 group and other 8 support data2 group
At the present, manager request to one devices to data 1 from data2.
How can we user EM ( or other way) to move one device to data1 from data2 diskgroup without damage database.
Please help me. this is emergency resuest due to data1 diskgroup without space and SA can not add a space in there right now.
Thanks very much
JimNo, you won't loose any data assuming you have enough space on other disks to move the data from the disk that is being dropped. Once run the drop command, asm automatically start rebalance process and it will start moving data from the disk that is being dropped to other available disks. I would give few mins to ASM to finish the rebalance process. You can check the reblance process by running the follwonig query. If the query results to nothing or zero records that means ASM is not doing any rebalances.
select * from v$asm_operation
you can also check the following query to check the disks
desc v$asm_disk
select * from asm_disk (or pick the fields you want to view such as name, status, header_status, mount_status, etc) -
Hi all!
I know that ASM is a mature product, features rich and much appreciated by DBAs.
I understand that for best throughput, one would be better to use ASM...
(I also understant that raw device mapping is the best configuration for performance - BUT I definitely would not recommend using RDM for the management complexity it adds..).
It does NOT seems simple to implement ASM here because of responsabilities (sysadmins vs dba).
So my question are (not RAC related):
1- Does anybody actually measured the difference in performance (between using ASM and NOT using ASM, i.e. using O/S filesystem)?
2- I know it is adviced as a best practices (for best throughput) to separate online redo logs and data files - but is realy that bad NOT to do it?
Otherwise said, how detrimental is it to merge logs with datafiles.
Any thoughts/references are welcome...
JocelynHi ,
ASM has few more additional feature which make it better than rest and available in 12C,
+ Priority rebalance --->> Now ASM will do rebalance depending on file type ,rather file number
+ Failgroup_repair_time -->> Similar to disk_repair_time ,it is failgroup
+ In true sense,disk online replace without impacting normal operation -->> Disk get replace on same slot of that diskgroup ,not on n+1th slot
+ Even read -->> Read will happen from any allocation
+ backing up additional blocks at ASM level. -->> backing up more asm metadata blocks of each disk which is in use in ASM within that disk.
+ scrubbing --->> Automatically detects logical corruption and try to fix it depending of few things at ASM level.
Even with same characteristics disks ,under different disk controller ,with stripping will have better performance comparing filesystem.
though ,it is not an apple to apple comparison.
With Priority rebalance ,your online redo logfile will be rebalance earlier that datafiles and availability will be faster .
--- These make ASM a better choice ..
Regards,
Aritra -
Hi folks,
what are benefit of rebalance in ASM?
thanks & regards.Hi,
ASM Rebalancing >>>>>>>>>>>>>>>>>>>>>>>
"Rebalancing" is the process of moving file extents onto or off of disks for the purpose of evenly distributing the I/O load of the diskgroup
It occurs asynchronously in the background and can be monitored
In a clustered environment, rebalancing for a disk group is done within a single ASM instance only and cannot be distributed across multiple cluster node to speed it up
ASM will automatically rebalance data on disks when disks are added or removed
The speed and effort placed on rebalancing can be controlled via a POWER LIMIT setting
POWER LIMIT controls the number of background processes involved in the rebalancing effort and is limited to 11. Level 0 means no rebalancing will occur
I/O performance is impacted during rebalancing, but the amount of impact varies on which disks are being rebalanced and how much they are part of the I/O workload. The default power limit was chosen so as not to impact application performance
Thanks,
Rajasekhar -
What is the failure group in ASM and the meaning of ASM assigns each disk
Hi
Please help me in understanding
what is the failure group in ASM and the meaning of "ASM assigns each disk to it's own failure group, by default"As you may have known ASM uses mirroring and striping of files. Mirroring is storing same compies/parts of files in different disks/controllers. When creating disk group which could consist of several disks, you have to assign disks at least to separate failure groups for normal redundancy , or three failure groups for High redundancy. This means that ASM will never assign mirrode copies/pieces of files to the same failure group. So, assigning disks to different failure groups you make sure mirrored copies are not on the same physical storage. Saying with other words, failure group gives your more abstract meaning based on which you can organize your physical disks contained in disk group.
That is why for normal redundancy at least two failure groups are needed, because there are one mirrored copy of each extent(allocation unit, to be exact) and for high redundancy the requirement is at least 3 failure groups, because each allocation unit has 2 mirrored copies, which should be on different failure group, consequently.
Hope, this explanation is helpful. -
Hi guys, I have a big issue to solve: I work on Solaris OS and Oracle 10.0.2 with ASM.
I can't delete a new (no tablespace are expanded till now) disk added to diskgroup (DGFC).
This is my situation:
select name, state FROM V$ASM_DISK where name like 'DGFC%';
NAME STATE
DGFC_0000 NORMAL
DGFC_0001 NORMAL
DGFC_0002 NORMAL
DGFC_0003 NORMAL
DGFC_0004 NORMAL
DGFC_0005 NORMAL
DGFC_0006 NORMAL
DGFC_0007 NORMAL
DGFC_0008 NORMAL <---- This is the last disk added (I would remove it)
Maybe this could be important: DGFC_0008 was dropped from another diskgroup and header_status has changed from CANDIDATE to FORMER, then I added to DGFC diskgroup in the classic way.
Sending ALTER DISKGROUP DGFC DROP DISK DGFC_0008; the situation change into
NAME STATE
DGFC_0008 HUNG
and log file alert_+ASM.log contains:
Fri Jan 14 21:18:08 2011
SQL> ALTER DISKGROUP DGFC DROP DISK DGFC_0008
Fri Jan 14 21:18:08 2011
NOTE: PST update: grp = 1
NOTE: requesting all-instance PST refresh for group=1
Fri Jan 14 21:18:08 2011
NOTE: PST refresh pending for group 1/0x22e8f203 (DGFC)
SUCCESS: refreshed PST for 1/0x22e8f203 (DGFC)
Fri Jan 14 21:18:13 2011
NOTE: starting rebalance of group 1/0x22e8f203 (DGFC) at power 1
Starting background process ARB0
ARB0 started with pid=12, OS id=5071
Fri Jan 14 21:18:13 2011
NOTE: assigning ARB0 to group 1/0x22e8f203 (DGFC)
Fri Jan 14 21:18:13 2011
WARNING: allocation failure on disk DGFC_0000 for file 3 xnum 30
Fri Jan 14 21:18:13 2011
Errors in file /users/app/oracle/admin/+ASM/bdump/+asm_arb0_5071.trc:
ORA-15041: diskgroup space exhausted
Fri Jan 14 21:18:13 2011
NOTE: stopping process ARB0
Fri Jan 14 21:18:16 2011
WARNING: rebalance not completed for group 1/0x22e8f203 (DGFC)
Fri Jan 14 21:18:16 2011
SUCCESS: rebalance completed for group 1/0x22e8f203 (DGFC)
NOTE: PST update: grp = 1
WARNING: grp 1 disk DGFC_0008 still has contents (45 AUs)
NOTE: PST update: grp = 1
This is /users/app/oracle/admin/+ASM/bdump/+asm_arb0_5071.trc:
Instance name: +ASM
Redo thread mounted by this instance: 0 <none>
Oracle process number: 12
Unix process pid: 5071, image: [email protected] (ARB0)
*** SERVICE NAME:() 2011-01-14 21:18:13.067
*** SESSION ID:(39.20) 2011-01-14 21:18:13.067
ARB0 relocating file +DGFC.3.1 (7 entries)
ORA-15041: diskgroup space exhausted
Anyone could help ??? Thanks a lotThanks a lot Levi,
The answer was into the Log: disk exhausted. Original diskgroup was quite full and asm can't rebalance correctly the data on the new disk (which datas??!!).
I solved adding a new disk (16GB) and alterering diskgroup DGFC. New space ready and disk dropped correctly.
Thanks a lot
Bye -
Oracle 10g RAC Database Migration from SAN to New SAN.
Hi All,
Our client has implemented a Two Node Oracle 10g R2 RAC on HP-UX v2. The Database is on ASM and on HP EVA 4000 SAN. The database size in around 1.2 TB.
Now the requirement is to migrate the Database and Clusterware files to a New SAN (EVA 6400).
SAN to SAN migration can't be done as the customer didn't get license for such storage migration.
My immediate suggestion was to connect the New SAN and present the LUNs and add the Disks from New SAN and wait for rebalance to complete. Then drop the Old Disks which are on Old SAN. Exact Steps To Migrate ASM Diskgroups To Another SAN Without Downtime. (Doc ID 837308.1).
Clients wants us to suggest alternate solutions as they are worried that presenting LUNs from Old SAN and New SAN at the same time may give some issues and also if re-balance fails then it may affect the database. Also they are not able to estimate the time to re-balance a 1.2 TB database across Disks from 2 different SAN. Downtime window is ony 48 hours.
One wild suggestion was to:
1. Connect the New SAN.
2. Create New Diskgroups on New SAN from Oracle RAC env.
3. Backup the Production database and restore on the same Oracle RAC servers but on New Diskgroups.
4. Start the database from new Diskgroup location by updating the spfile/pfile
5. Make sure everything is fine then drop the current Diskgroups from Old SAN.
Will the above idea work in Production env? I think there is a lot of risks in doing the above.
Customer does not have Oracle RAC on Test env so there isn't any chance of trying out any method.
Any suggestion is appreciated.
Rgds,
Thiru.user1983888 wrote:
Hi All,
Our client has implemented a Two Node Oracle 10g R2 RAC on HP-UX v2. The Database is on ASM and on HP EVA 4000 SAN. The database size in around 1.2 TB.
Now the requirement is to migrate the Database and Clusterware files to a New SAN (EVA 6400).
SAN to SAN migration can't be done as the customer didn't get license for such storage migration.
My immediate suggestion was to connect the New SAN and present the LUNs and add the Disks from New SAN and wait for rebalance to complete. Then drop the Old Disks which are on Old SAN. Exact Steps To Migrate ASM Diskgroups To Another SAN Without Downtime. (Doc ID 837308.1).
Clients wants us to suggest alternate solutions as they are worried that presenting LUNs from Old SAN and New SAN at the same time may give some issues and also if re-balance fails then it may affect the database. Also they are not able to estimate the time to re-balance a 1.2 TB database across Disks from 2 different SAN. Downtime window is ony 48 hours.Adding and removing LUNs online is one of the great features of ASM. The Rebalance will be perfomed under SAN. No downtime!!!
If your customer is not entrusting on ASM. So Oracle Support can answer all doubt.
Any concern .. Contat Oracle Support to guide you in the best way to perform this work.
>
One wild suggestion was to:
1. Connect the New SAN.
2. Create New Diskgroups on New SAN from Oracle RAC env.
3. Backup the Production database and restore on the same Oracle RAC servers but on New Diskgroups.
4. Start the database from new Diskgroup location by updating the spfile/pfile
5. Make sure everything is fine then drop the current Diskgroups from Old SAN.
ASM Supports many Terabytes, if you need to migrate 3 Database with 20TB each using this way described above would be very laborious .. .. So add and remove Luns online is one feature that must work.
Take the approval from Oracle support and do this work using the ASM Rebalance.
Regards,
Levi Pereira
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