RSS and BLOBs
Nate Hicks asked whether RSS still cannot work with a blobspace. Jacques Renaut and Art Kagel explained blobspace blob data is not logged, so it is not replicated by HDR or RSS. Art's alternatives: IN TABLE blobs, logged smart blobs, LVARCHAR if under 32K, Enterprise Replication (works with blobspaces), or filesystem storage with disk-level replication.
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Quick question...maybe... We're using RSS but we have a BLOB space. According to developer works http://www.ibm.com/developerworks/data/tutorials/db2-cert9195/section9.html RSS isn't able to restore a primary if the DB contains a BLOB space. Is this still true? If so is there any kind of workaround other than not using RSS? Thanks, Nate
Original post: Quick question...maybe... We're using RSS but we have a BLOB space. According to developer works http://www.ibm.com/developerworks/data/tutorials/db2-cert9195/section9.html RSS isn't able to restore a primary if the DB contains a BLOB space. Is this still true? If so is there any kind of workaround other than not using RSS? Thanks, Nate Response: Well, when using RSS/HDR the data in your blobspaces is not replicated (when it's modified, inserted, or deleted after the initial archive restore to set up the server) to the secondary servers. So then from the developer works article, it then makes sense that you can not take an external back of your RSS server and restore it on your primary and be ok, because any modifications you made to the data in the blobspaces would not be present on the RSS server (since it didn't get logged, it can't get replicated). The work around would be to move your blobs from being stored in blobspaces to being stored in table, then it would get logged and then replicated in the HDR/RSS case. Jacques Renaut IBM Informix Advanced Support APD Team
Shouldn't the L flag not be present in onstat -d output then?
7000000226fd870 10 0x40811 27 2 204800 NLBB informix db
Infocenter says L is Being logically recovered.
Original post:
Shouldn't the L flag not be present in onstat -d output then?
7000000226fd870 10 0x40811 27 2 204800 NLBB informix db
Infocenter says L is Being logically recovered.
Response:
Well, it technically is being logically recovered, as some information about
blobspaces does get logical logged (like changes to the free map pages), but
the data in the blob pages itself isn't logged so that's why it doesn't work
HDR/RSS.
See
http://pic.dhe.ibm.com/infocenter/informix/v121/index.jsp?topic=%2Fcom.ibm.admin
.doc%2Fids_admin_0920.htm
Jacques Renaut
IBM Informix Advanced Support
APD Team
Blobspace blobs do not replicate using HDR or RSS (IB that they cannot be used with SDS either, but not certain about that). It's not the blobspace per ce, but the fact that blobs stored in a blobspace are not logged. Recovery is handled by always creating a new copy of the blob and not deleting the older copy until the server is next archived making the new version safe. Anyway, what to do instead? You can either convert the column to an IN TABLE blob so that it is logged (might want to move the table to wider pages though unless the blobs are very small), convert it to a logged smart blob, convert it to an LVARCHAR columns if the blobs are all smaller than 32K, or use Enterprise Replication. Blobspace blobs do work with ER. Final option, move the blob data to filesystem space and replicate the files to the secondary machine separately using disk level replication (ala EMC's Symetrics, etc.) Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Tue, May 14, 2013 at 11:59 AM, NATE HICKS <nathaniel.hicks@trnswrks.com>wrote: > Quick question...maybe... > We're using RSS but we have a BLOB space. According to developer works > http://www.ibm.com/developerworks/data/tutorials/db2-cert9195/section9.html > RSS isn't able to restore a primary if the DB contains a BLOB space. Is > this > still true? If so is there any kind of workaround other than not using RSS? > > Thanks, > Nate > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > WebRep currentVote noRating noWeight --089e01228d683767ae04dcb0fb6c