X Series hot swappable drives 2

[JohnBates]

Hi server experts,

I'm hoping to get 2 model 345 X Series servers.

The smallest hot-swappable drive on IBM's web site is 18.2 GB . I wil get 5 or 6 drives to be able to utilize RAID 5 protection.... but I sure dont need 100 + GB of space. Realy don't need more than 30 GB but that's less than a new PC has today.

Does anyone know if the 9GB drives will work in the X-Series
servers?

Thanks, John

 

[JohnBates]

... and I should have said that these must be SCSI swappable drives.

 

[victorv]

hi,
sometime to use in external storage fo cluster use
I need a little but mirrored disk to realize "Quorum device"
but the minimum I can resell is 2x18Gb disks .

The x345 (I have installed 2 last weeks), has one integrated SCSI adapter (a chip) named LSI Logic 53C1030:
this chip can only realize Raid 1 ( + hot spare disk )
but you cannot make a Raid5.

To make a Raid5 Array, using the x345 backplane,
you have to install the 5i adapter in slot 2.
This is a low-cost adapter, at 320 MB/sec, but this
card hides the LSI: after you have installed 5i, you don't
see more the LSI. This card has not external link, but
using a optional cable, you can connect its channel B to
an external Storage.

1) Whitout 5i, you can buy 2x36Gb hotswap disks and make a mirror array in which you can put System and Data.

2) With 5i you can buy 3x18 disks and make a Raid5 Array.

3) With 5i, you can make 2 arrays, one for system, the other
for data (ie 2x18Gb mirror to obtain C: disk fir system, +
2 or 3 x 18-36 Gb disk for Data)

The Solution #3 is the most clean, but you need minimum 4 disks + the 5i adapter.

The Solution 1,2 are similar, but I belive the #1 is cheapest

Sol 1: 2x36Gb disk
Sol 2: 3x18Gb disk + 5i adapter
Sol 3: minimum 4 18gb disk + 5i adapter.

You can also make a 2.5 solution: a mix between 2 and 3:
now you buy only 2x18Gb disk and 5i and you make a mirror
array of 18Gb size, and here you install OS.
In future, you can buy and add (hot swap) any other disk
combination, building a new volume (Raid 0,1,5), without
needing to reinstall OS

I vote for 2.5 solution !

bye

 

[catorze]

The smallest supported HDD for the x345 is 18GB. You definitely want to be in a supported configuration. Using all 6 hot-swap bays, and a RAID Controller, you can define one of the HDDs as a Hot Spare (standby HDD in the event of a failure) and configure a single Array with a RAID5 logical drive from the remaining HDDs, yielding the effective storage of ~72GB (n-1 HDD or 4x18GB = 72GB). If you use only five bays, you can still have a hot spare and a RAID 5 logical drive with the remaining 4 HDDs, yielding ~54GB of storage space. The benefit of this arrangement is that you can survive the failure of two HDDs (one at a time) and still be up and running without intervention.

 

[JohnBates]

thanks catorze,

If I understand correctly, the minimum number of drives to achieve RAID 5 is 3... right? So could I have 3 and a spare drive (not installed)? Will the performance be OK with only 3 drives? The 18.2 GB drives are $275 so I can save a significant amount of money by running with only 3.

Thanks, John

 

[catorze]

Yes, the minimum for RAID 5 is 3 HDDs, which will yield the data storage space of 2HDDs. So you can have 3 and a spare INSTALLED (defined as a Hot Spare) - which will facilitate auto-magic failover if one dies while you happen to not be around. That way, you can survive two HDD failures (although not at the same time) and still have access to your data. Performance on three HDDs should be good, provided your not running a huge database with lots of users. My guess in not, given your limited space requirements.

 

[JohnBates]

you are correct catorze,

There will be at the most 15 "users" or services connected to this server. The db is SQL Server 2000 withe merge replication in place to keep 2 servers "in-sync". The db will not be more than 500MB to 1GB. But lots of I/O.
I think the 10,000 RPM drives and the Xeon 2.6 Ghz configuration will be more than adequate (considering that today this system is running on Netfinity PII and slower drives)


Sounds like 3 active drives will suffice. Tks for your tips.
John

 

[bschreib]

I have another question to go along with this. I have a 345 x server that we have been using for a few months. Needing more space we opted for local storage so we bought the 5i controller to end up with VICTORV's solution 3 above. All the information I have is telling me I am going to lose all the data that is on the mirrored c drives?? That can't be accurate though.

 

[JohnBates]

bschreib - I noticed that you are a new member. Welcome. This is a very good forum for us IT/MIS folks. You will prob get better results by starting a new thread for your question above.

John