| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
 |
 | |||
| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
|
| |||
Home -> Community -> Mailing Lists -> Oracle-L -> RE: Sizing - RAC, storage subsystem EMC
Rachel - You make some excellent points. I am speaking to the situation
where the site doesn't have a performance problem. When there is a problem,
everyone is much more eager to accept suggestions.
As you point out, the DBA usually doesn't buy hardware, so the hardware people tend to take that as intruding on their responsibilities with the intent of making them look bad. So they react defensively. And for every reason you can quote that RAID5 is bad, they will provide a countervailing reason why your information isn't valid. At least not with their hardware configuration. And the hardware vendor is very helpful in giving them information that will bolster their arguments. Then again, your average DBA usually isn't a foremost expert in disk configurations.
A consultant that is paid to come in and solve a performance problem then leave doesn't face the longer-term issues that arise from making ones colleagues look bad. My point is that there are some battles one wouldn't want to win.
Dennis Williams
DBA, 80%OCP, 100% DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com
-----Original Message-----
Sent: Friday, May 23, 2003 8:27 PM
To: Multiple recipients of list ORACLE-L
Here's the thing. Disks are cheap. Maybe. But buying 5 disks is still cheaper than buying 10 disks. And it is NOT the people who actually work with the disks (DBAs, Sysadmins, even developers) who have the authority to order the disks.
You need places and floor space to put the disks as well. It's not like you can just hang them from the ceiling.
And even more so these days, and it seems most especially in the US companies, companies are trying to cut costs to the bone (we just went through an exercise where we practically had to jump through hoops just to get more memory for a production system which obviously needed the memory). And cutting costs means as few disks as possible, means reuse, consolidate and do without.
It kind of reminds me of one of the sayings my parents (who grew up during the Great Depression here) have told me of that time: "use it up, make it do, or do without"
we're in the "do without" phase
Rachel
--- Mogens_Nørgaard <mln_at_miracleas.dk> wrote:
> I'm beginning to think that we're having this wonderful discussion
> about
> RAID-5 time and again because the vendors keep coming up with
> arguments
> to prove that the general laws of nature don't apply to this
> particular
> technology.
>
> In the 50s we had a prime minister here in Denmark that said to the
> assembled parliament: "If that's the facts, then I deny the facts".
> Somehow you have to admire a guy like that.
>
> Since disks are now cheap, how on Earth is it that we allow various
> IO-vendors to bundle cheap disks, expensive cache which we won't
> need,
> and stupid technologies like RAID-5 into a box called SAN/NAS or
> whatever and charge 42 billion units of some real currency for it?
>
> Why don't we take our swords and shotguns and AK-74s (that's the
> small
> calibre), and point them at them until they actually just bundle a
> bunch
> of inexpensive disks into RAID 1+0 which we ALL know is superior to
> RAID-S, RAID-5 (notice how S looks like 5 - it's no coincidence).
> It's
> superior to RAID 0+1 even. It doesn't require (the expensive) cache
> either.
>
> One of my wonderful experiences was with a TelCo here, where the
> vendor
> kept saying that they should of course just add cache if performance
> wasn't sufficient. When they finally reached the 32GB (yep,
> thirty-two
> giga-bytes) of cache alone, they gave up, ripped the stuff apart and
> reconfigured it as RAID 0+1 and it finally performed on the small
> writes. We all loved it - except possibly the disk-vendor, who kept
> saying RAID-<some letter that resembles the number 5> was of course
> fantastic, and that they shouldn't listen to all these bitter, old,
> twisted Oracle people who just hated RAID-5 and the likes ... ahhh...
>
> just because!
>
> It's got nothing to do with Oracle or not. It's got to do with money
> and
> brains.
>
> RAID 1+0 is the best you can buy.
> RAID 0+1 is almost as good.
> RAID 5 sucks - in all its disguises and permutations - compared to
> 0+1
> or 1+0.
>
> If RAID-5 is good enough for you, fine. But remember to test the
> good,
> old restore of the backup and time it so that you're prepared if it
> happens. It should of course take about four times as long as the
> backup.
>
> As Connor said (and Cary has said it in his excellent, but futile,
> RAID-5 paper) it's when you really, really need disk performance that
>
> RAID-5 will let you down.
>
> Yo.
>
> Mogens
>
> Arun Annamalai wrote:
>
> > Hi George.
> >
> > I would recommend go with Raid 5 and its not that one transaction
> > triggers that many writes as you have mentioned/calculated.
> > It is all buffered with recovery mechanism.
> >
> > Have you thought about Raid4(Network appliance) hardware. (I am no
> way
> > affliated with Network appliance, except that we use in our site.)
> > Most of the big names use them, such as
> > 1, Yahoo. (you can see network appliance logo when you logout of
> your
> > yahoo email account)
> > 2. Oracle
> > 3. Southwest airlines.
> >
> > I mean Yahoo, Southwest Airlnes are all heavy transaction oriented
> > shop on a given per minute interval.
> > The most common overhead of SAN is that the throughput of the
> switch
> > that connects your server to the san storage.
> >
> > Also, heard that Net App (best in NAS) is colloborating with
> Hitachi
> > (best in SAN storage) to get the best technology for storage and
> > thoroughput performance. But this might take a while or might
> already
> > be in the market. Check out with your local Hitachi or Netapp
> > representatives.
> >
> > Hope this helps.
> > -Arun.
> >
> >
> > ----- Original Message -----
> > From: George.Leonard_at_za.didata.com
> > <mailto:George.Leonard_at_za.didata.com>
> > To: Multiple recipients of list ORACLE-L
> > <mailto:ORACLE-L_at_fatcity.com>
> > Sent: Tuesday, May 20, 2003 2:06 AM
> > Subject: Sizing - RAC, storage subsystem EMC
> >
> > Hi all, hope you can give some input ideas.
> >
> >
> >
> > I am in the process of designing a system for a client of ours
> for
> > a proposal
> >
> >
> >
> > The sizing information I have been given is as follows.
> >
> >
> >
> > 58.1 million tickets/day at 351 bytes per record. The record
> was
> > complete populated (all columns filled to max) in a table and
> then
> > analyzed. Average row size 351 bytes.
> >
> > =~ 19 GB/day. Raw data. Plus overhead (indexes, temp space,
> > rollback, some other data etc) here and there I have requested
> 5 TB.
> >
> >
> >
> > We need to keep records for a month. Table design I am looking
> at
> > is a date partition with a second level hash partition. This is
> so
> > that I can move data in the oldest week/table space off line
> and
> > write them to optical storage for possible retrieval at a later
> > date (requirement).
> >
> >
> >
> > Of course this will be on locally managed table spaces with
> auto
> > storage management for segments.
> >
> >
> >
> > Hardware:
> >
> > The database will be a Oracle RAC 9.2.0.4 on Sun cluster 3
> build
> > on 2 x Sun StarFire V880, 4 CPU's, 4 GB RAM each,
> >
> > Connected to an EMC SAN via Fiber Channel
> >
> >
> >
> > I do not have more information about the EMC array at the
> moment.
> > Hitachi has been mentioned. (excuse the spelling)
> >
> >
> >
> > Question I have.
> >
> >
> >
> > I have been asked how many writes the Database will be doing to
> > the SAN per second.
> >
> > I have determined that I should expect about 2000
> tickets/second.
> >
> > The table in question will have 2 indexes.
> >
> >
> >
> > Now following rough guessing I said I should expect at least 16
> > 000 writes/second
> >
> >
> >
> > This was done by say/assuming
> >
> >
> >
> > 2 writes for the redo log files (2 members)
> >
> > 2 writes for the control files (2 control files)
> >
> > 2 writes to index blocks
> >
> > 1 write to undo table space block
> >
>
=== message truncated ===
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Rachel Carmichael INET: wisernet100_at_yahoo.com Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: DENNIS WILLIAMS INET: DWILLIAMS_at_LIFETOUCH.COM Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Sun May 25 2003 - 17:01:39 CDT
 |
 |