Hello. Has anyone every used the SST option "Work with removing units from configuration" to remove disks that are in a RAID5 parity set?  

We are hoping to make several drives non-configured in order to use them for an IASP. (We are planning to employ PowerHA eventually.)

I'm just wondering whether or not it will work OK and wondering what I can expect. 

We are on a Power9 41G at V7R4. We have 17 spinning drives in one RAID set with a hot spare. So the system unit is at capacity as far as disk, and we do not have an additional disk enclosure. We are only running at 41% usage on the system ASP so there is plenty of room to take some drives for the IASP.

Incidentally, I did ask IBM hardware support about this but I am interested to hear of real-world occurrences.

Thanks,

John

Hello. Has anyone every used the SST option "Work with removing units from configuration" to remove disks that are in a RAID5 parity set?  

We are hoping to make several drives non-configured in order to use them for an IASP. (We are planning to employ PowerHA eventually.)

I'm just wondering whether or not it will work OK and wondering what I can expect. 

We are on a Power9 41G at V7R4. We have 17 spinning drives in one RAID set with a hot spare. So the system unit is at capacity as far as disk, and we do not have an additional disk enclosure. We are only running at 41% usage on the system ASP so there is plenty of room to take some drives for the IASP.

Incidentally, I did ask IBM hardware support about this but I am interested to hear of real-world occurrences.

Thanks,

John

------------------------------
John Paisley
------------------------------

Hello. Has anyone every used the SST option "Work with removing units from configuration" to remove disks that are in a RAID5 parity set?  

We are hoping to make several drives non-configured in order to use them for an IASP. (We are planning to employ PowerHA eventually.)

I'm just wondering whether or not it will work OK and wondering what I can expect. 

We are on a Power9 41G at V7R4. We have 17 spinning drives in one RAID set with a hot spare. So the system unit is at capacity as far as disk, and we do not have an additional disk enclosure. We are only running at 41% usage on the system ASP so there is plenty of room to take some drives for the IASP.

Incidentally, I did ask IBM hardware support about this but I am interested to hear of real-world occurrences.

Thanks,

John

Thank you both for your replies! It is much appreciated.

I am not so much concerned about creating an additional RAID-5 set for the IASP drives. As long as I know that it will work OK with both the SYSBAS ASP and the IASP in the same existing RAID-5 set, I am satisfied with that.  All of the disks will be protected by RAID-5 with hot spare. 

I think you have answered my question, Satid, as to what I can expect from the remove procedure in SST:

The disks will show up as non-configured but the RAID set will be preserved as it was.   Please correct me if I'm wrong.

This would be a convenient method, as you said.

Thanks again!

John

Hello. Has anyone every used the SST option "Work with removing units from configuration" to remove disks that are in a RAID5 parity set?  

We are hoping to make several drives non-configured in order to use them for an IASP. (We are planning to employ PowerHA eventually.)

I'm just wondering whether or not it will work OK and wondering what I can expect. 

We are on a Power9 41G at V7R4. We have 17 spinning drives in one RAID set with a hot spare. So the system unit is at capacity as far as disk, and we do not have an additional disk enclosure. We are only running at 41% usage on the system ASP so there is plenty of room to take some drives for the IASP.

Incidentally, I did ask IBM hardware support about this but I am interested to hear of real-world occurrences.

Thanks,

John

Thank you both for your replies! It is much appreciated.

I am not so much concerned about creating an additional RAID-5 set for the IASP drives. As long as I know that it will work OK with both the SYSBAS ASP and the IASP in the same existing RAID-5 set, I am satisfied with that.  All of the disks will be protected by RAID-5 with hot spare. 

I think you have answered my question, Satid, as to what I can expect from the remove procedure in SST:

The disks will show up as non-configured but the RAID set will be preserved as it was.   Please correct me if I'm wrong.

This would be a convenient method, as you said.

Thanks again!

John

Hello. Has anyone every used the SST option "Work with removing units from configuration" to remove disks that are in a RAID5 parity set?  

We are hoping to make several drives non-configured in order to use them for an IASP. (We are planning to employ PowerHA eventually.)

I'm just wondering whether or not it will work OK and wondering what I can expect. 

We are on a Power9 41G at V7R4. We have 17 spinning drives in one RAID set with a hot spare. So the system unit is at capacity as far as disk, and we do not have an additional disk enclosure. We are only running at 41% usage on the system ASP so there is plenty of room to take some drives for the IASP.

Incidentally, I did ask IBM hardware support about this but I am interested to hear of real-world occurrences.

Thanks,

John

Thank you both for your replies! It is much appreciated.

I am not so much concerned about creating an additional RAID-5 set for the IASP drives. As long as I know that it will work OK with both the SYSBAS ASP and the IASP in the same existing RAID-5 set, I am satisfied with that.  All of the disks will be protected by RAID-5 with hot spare. 

I think you have answered my question, Satid, as to what I can expect from the remove procedure in SST:

The disks will show up as non-configured but the RAID set will be preserved as it was.   Please correct me if I'm wrong.

This would be a convenient method, as you said.

Thanks again!

John

Hello. Has anyone every used the SST option "Work with removing units from configuration" to remove disks that are in a RAID5 parity set?  

We are hoping to make several drives non-configured in order to use them for an IASP. (We are planning to employ PowerHA eventually.)

I'm just wondering whether or not it will work OK and wondering what I can expect. 

We are on a Power9 41G at V7R4. We have 17 spinning drives in one RAID set with a hot spare. So the system unit is at capacity as far as disk, and we do not have an additional disk enclosure. We are only running at 41% usage on the system ASP so there is plenty of room to take some drives for the IASP.

Incidentally, I did ask IBM hardware support about this but I am interested to hear of real-world occurrences.

Thanks,

John

Dear Andreu and John

>>>> I think you must assure that the load disk is not removed from the original ASP. <<<<

This is not to worry about at all because the SST tool DOES NOT show the load source disk (disk unit number 1) in the screen for disk removal from ASP as shown below: 

Thank you both for your replies! It is much appreciated.

I am not so much concerned about creating an additional RAID-5 set for the IASP drives. As long as I know that it will work OK with both the SYSBAS ASP and the IASP in the same existing RAID-5 set, I am satisfied with that.  All of the disks will be protected by RAID-5 with hot spare. 

I think you have answered my question, Satid, as to what I can expect from the remove procedure in SST:

The disks will show up as non-configured but the RAID set will be preserved as it was.   Please correct me if I'm wrong.

This would be a convenient method, as you said.

Thanks again!

John

Hello. Has anyone every used the SST option "Work with removing units from configuration" to remove disks that are in a RAID5 parity set?  

We are hoping to make several drives non-configured in order to use them for an IASP. (We are planning to employ PowerHA eventually.)

I'm just wondering whether or not it will work OK and wondering what I can expect. 

We are on a Power9 41G at V7R4. We have 17 spinning drives in one RAID set with a hot spare. So the system unit is at capacity as far as disk, and we do not have an additional disk enclosure. We are only running at 41% usage on the system ASP so there is plenty of room to take some drives for the IASP.

Incidentally, I did ask IBM hardware support about this but I am interested to hear of real-world occurrences.

Thanks,

John

Thank you both for your replies! It is much appreciated.

I am not so much concerned about creating an additional RAID-5 set for the IASP drives. As long as I know that it will work OK with both the SYSBAS ASP and the IASP in the same existing RAID-5 set, I am satisfied with that.  All of the disks will be protected by RAID-5 with hot spare. 

I think you have answered my question, Satid, as to what I can expect from the remove procedure in SST:

The disks will show up as non-configured but the RAID set will be preserved as it was.   Please correct me if I'm wrong.

This would be a convenient method, as you said.

Thanks again!

John

Hello. Has anyone every used the SST option "Work with removing units from configuration" to remove disks that are in a RAID5 parity set?  

We are hoping to make several drives non-configured in order to use them for an IASP. (We are planning to employ PowerHA eventually.)

I'm just wondering whether or not it will work OK and wondering what I can expect. 

We are on a Power9 41G at V7R4. We have 17 spinning drives in one RAID set with a hot spare. So the system unit is at capacity as far as disk, and we do not have an additional disk enclosure. We are only running at 41% usage on the system ASP so there is plenty of room to take some drives for the IASP.

Incidentally, I did ask IBM hardware support about this but I am interested to hear of real-world occurrences.

Thanks,

John

Hi John,

Correct, you don't lost RAID protection if you use this option (removing units from configuration). This option only removes discs from ASP where they are located.

Thank you both for your replies! It is much appreciated.

I am not so much concerned about creating an additional RAID-5 set for the IASP drives. As long as I know that it will work OK with both the SYSBAS ASP and the IASP in the same existing RAID-5 set, I am satisfied with that.  All of the disks will be protected by RAID-5 with hot spare. 

I think you have answered my question, Satid, as to what I can expect from the remove procedure in SST:

The disks will show up as non-configured but the RAID set will be preserved as it was.   Please correct me if I'm wrong.

This would be a convenient method, as you said.

Thanks again!

John

Hello. Has anyone every used the SST option "Work with removing units from configuration" to remove disks that are in a RAID5 parity set?  

We are hoping to make several drives non-configured in order to use them for an IASP. (We are planning to employ PowerHA eventually.)

I'm just wondering whether or not it will work OK and wondering what I can expect. 

We are on a Power9 41G at V7R4. We have 17 spinning drives in one RAID set with a hot spare. So the system unit is at capacity as far as disk, and we do not have an additional disk enclosure. We are only running at 41% usage on the system ASP so there is plenty of room to take some drives for the IASP.

Incidentally, I did ask IBM hardware support about this but I am interested to hear of real-world occurrences.

Thanks,

John

Hello. Has anyone every used the SST option "Work with removing units from configuration" to remove disks that are in a RAID5 parity set?  

We are hoping to make several drives non-configured in order to use them for an IASP. (We are planning to employ PowerHA eventually.)

I'm just wondering whether or not it will work OK and wondering what I can expect. 

We are on a Power9 41G at V7R4. We have 17 spinning drives in one RAID set with a hot spare. So the system unit is at capacity as far as disk, and we do not have an additional disk enclosure. We are only running at 41% usage on the system ASP so there is plenty of room to take some drives for the IASP.

Incidentally, I did ask IBM hardware support about this but I am interested to hear of real-world occurrences.

Thanks,

John

Hi John, 

For precaution, don't forget to back up your system before removing disk. 

I'm not familiar with your production and don't know why 17 disks were needed on the system at startup, but from what I always hear from IBM and for the IBM i in particular the more arms (disks) the better for performance (i/o). So by removing disks from the cluster, you may be increasing processing times. You might want to run a performance analysis before doing so, to confirm that removing disks will not impact your production.

Regards

Hello. Has anyone every used the SST option "Work with removing units from configuration" to remove disks that are in a RAID5 parity set?  

We are hoping to make several drives non-configured in order to use them for an IASP. (We are planning to employ PowerHA eventually.)

I'm just wondering whether or not it will work OK and wondering what I can expect. 

We are on a Power9 41G at V7R4. We have 17 spinning drives in one RAID set with a hot spare. So the system unit is at capacity as far as disk, and we do not have an additional disk enclosure. We are only running at 41% usage on the system ASP so there is plenty of room to take some drives for the IASP.

Incidentally, I did ask IBM hardware support about this but I am interested to hear of real-world occurrences.

Thanks,

John

Dear John

>>>>  You might want to run a performance analysis before doing so, to confirm that removing disks will not impact your production. <<<<

For this purpose, you can use the tool IBM i Performance Data Investigator (PDI) from Navigator for i GUI.  Use the performance chart named Disk Throughput Overview for Disk Pools and Physical Disk IO Overview - Basic that look like these:

The point is to take note of disk response time at peak MB/sec. and peak Disk IOPS period(s). If response time does not degrade too much higher than 5 millisec. (I assume HDD rather than SSD here) and/or is not so for a long period of time (say, less than 15 minutes), you are still in good shape.   You should look at these charts at peak workload day(s) and you should look at them BEFORE and AFTER you implement PowerHA for i for comparison. 

Hi John, 

For precaution, don't forget to back up your system before removing disk. 

I'm not familiar with your production and don't know why 17 disks were needed on the system at startup, but from what I always hear from IBM and for the IBM i in particular the more arms (disks) the better for performance (i/o). So by removing disks from the cluster, you may be increasing processing times. You might want to run a performance analysis before doing so, to confirm that removing disks will not impact your production.

Regards

Hello. Has anyone every used the SST option "Work with removing units from configuration" to remove disks that are in a RAID5 parity set?  

We are hoping to make several drives non-configured in order to use them for an IASP. (We are planning to employ PowerHA eventually.)

I'm just wondering whether or not it will work OK and wondering what I can expect. 

We are on a Power9 41G at V7R4. We have 17 spinning drives in one RAID set with a hot spare. So the system unit is at capacity as far as disk, and we do not have an additional disk enclosure. We are only running at 41% usage on the system ASP so there is plenty of room to take some drives for the IASP.

Incidentally, I did ask IBM hardware support about this but I am interested to hear of real-world occurrences.

Thanks,

John

Thanks again Satid. Based on the chart below, which was taken on a typical busy day, Wed, Oct 2nd, it looks like we are in pretty good shape for the time being - pre-PowerHA.  Although, I am not sure what equates to "response time". Is it "Average Service Time" or "Average Wait Time" or a combination of the two?

Thanks,

John

------------------------------
John Paisley

Original Message:
Sent: Fri October 04, 2024 09:06 PM
From: Satid S
Subject: Removing disk units from configuration using SST

Dear John

>>>>  You might want to run a performance analysis before doing so, to confirm that removing disks will not impact your production. <<<<

For this purpose, you can use the tool IBM i Performance Data Investigator (PDI) from Navigator for i GUI.  Use the performance chart named Disk Throughput Overview for Disk Pools and Physical Disk IO Overview - Basic that look like these:

The point is to take note of disk response time at peak MB/sec. and peak Disk IOPS period(s). If response time does not degrade too much higher than 5 millisec. (I assume HDD rather than SSD here) and/or is not so for a long period of time (say, less than 15 minutes), you are still in good shape.   You should look at these charts at peak workload day(s) and you should look at them BEFORE and AFTER you implement PowerHA for i for comparison. 

------------------------------
Satid S

Original Message:
Sent: Fri October 04, 2024 11:25 AM
From: Virgile VATIN
Subject: Removing disk units from configuration using SST

Hi John, 

For precaution, don't forget to back up your system before removing disk. 

I'm not familiar with your production and don't know why 17 disks were needed on the system at startup, but from what I always hear from IBM and for the IBM i in particular the more arms (disks) the better for performance (i/o). So by removing disks from the cluster, you may be increasing processing times. You might want to run a performance analysis before doing so, to confirm that removing disks will not impact your production.

Regards

------------------------------
Virgile VATIN

Original Message:
Sent: Wed October 02, 2024 09:16 AM
From: John Paisley
Subject: Removing disk units from configuration using SST

Hello. Has anyone every used the SST option "Work with removing units from configuration" to remove disks that are in a RAID5 parity set?  

We are hoping to make several drives non-configured in order to use them for an IASP. (We are planning to employ PowerHA eventually.)

I'm just wondering whether or not it will work OK and wondering what I can expect. 

We are on a Power9 41G at V7R4. We have 17 spinning drives in one RAID set with a hot spare. So the system unit is at capacity as far as disk, and we do not have an additional disk enclosure. We are only running at 41% usage on the system ASP so there is plenty of room to take some drives for the IASP.

Incidentally, I did ask IBM hardware support about this but I am interested to hear of real-world occurrences.

Thanks,

John

------------------------------
John Paisley
------------------------------