RAID stands for Redundant Array of Independent Disks.

RAID is data storage technology that allows multiple drives to be used together as a single virtual drive for reasons such as fault tolerance, reliability and performance.

There are several different levels of RAID that determine how the data is stored and the level of redundancy achieved across the drives.

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My client has a 12-bay Synology DiskStation DS3617xs NAS filled with 14TB Seagate IronWolf Pros.  It will be used in an adjacent building with Active Backup for Business to backup the server and 40 workstations.

Sadly, according to support, triple parity isn't an option with Synology, so I'm trying to decide whether it's reasonably safe to go with RAID6 or if the only logical choice is RAID10.

I've understood for a while that the size of modern hard drives makes RAID5 a bad idea due to the likelihood of an unrecoverable read error during a rebuild.  I've seen a small amount of discussion on whether RAID6 is a good idea, but haven't come across any details other than rebuild time.  I have no first-hand experience for what kind of duration to expect when rebuilding a 140TB array.

My own take on whether RAID6 is reasonably safe is that a rebuild would only fail with a single drive failure if two of the remaining drives both had UREs on sectors that contain the exact same data.  Granted, if you have two concurrent drive failures, you're in the same boat as with one drive failure on RAID5, nervously biting your nails and praying that the rebuild finishes.

Is my understanding of the minimal risk involved with UREs and RAID6 accurate?  How much time is it likely to take to rebuild after a drive failure?

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I wanted to know if it would be smart to run Seagate Nytro Enterprise SSD mixed use drives in Raid 5
I have read mixed reviews about running ssd's in Raid 5 on a server. The server will have a few VM's and be a file server as well.
The drive I was looking at is the XA1920ME10063

This question is for product recommendations for LSI MegaRaid cards.  I have been using the Megaraid LSI 9260-4i SATA RAID card with BBU for c. 5 years with great success and, knock on wood, 0 card failures or issues.  Unfortunately, the card has been out of production and EOL for c. 5 or 6 years now, so I figure for future setups I need to move on to another card that is in production, being supported by Broadcom, and getting ongoing firmware updates.  I called into Broadcom storage support and was advised to look into using the 9361-4i RAID card with CacheVault daughtercard for future setups.

Street pricing for the 9260-4i was typically $260 for the card and $160 for the BBU.
I'm seeing pricing for the 9361-4i at c. $350 and c. $120 for the CacheVault daughtercard.

Note that I use the MegaRAID cards for mostly in-house operations, or for secondary and peripheral client servers.  For primary client operations - SQL, Exchange etc. - I always use Dell servers.

My typical server setup when using MegaRAID is a simple one - SATA drives, either RAID-1 or RAID-5, though RAID-6 is possible where justified.  Add an additional drive as a hot spare and ensure email notifications for status updates and it's a reliable setup.

I'd appreciate any feedback and recommendations from pros who have experience with these cards as to whether the 9361-4i / 8i is the way to go, or if you recommend I standardize on a different adapter, and which one you've had good …
I just purchased a HP ProLiant DL380 Gen10. I have 6 2.4TB drives configured with RAID10 ADM. When I load Windows, I only show I am getting just under 5TB. If my calculations are correct, shouldn't I get over 7?ILO RAID Config
Am I wrong in my calculations?
Hi, we have a new Dell PowerEdge R540 and I'm looking for opinions on how best to configure the RAID(s). The system has 12 - 8TB SATA drives, PERC controller and has 512GB of RAM. The system will be a Hyper-V Host and will have many (probably a dozen or more) Hyper-V Virtual Machines on it. Some will be database servers like Oracle and SQL and others will be application servers and file servers. The OS will be Windows 2016. The VMs will be mostly 2016/2012 servers with a couple of W10 workstations sprinkled in. Interested in knowing how you would configure those drives. I usually like to use the hot spare option especially if the RAID only allows one drive failure. Years ago we had a RAID (5 I believe) with no hot spare and we lost two drives at the same time and all of our VMs … definitely would not want to go through that again. Thanks for your input.
My WD DL4100 NAS device has become inaccesible. I cant ping its ip address and it seems to be stuck in a power cycle loop. The disk 4 disks it contains are setup in a
RAID 5 configuration.

We have an identical NAS device that is being used for another purpose.

Would it be possible to simply move the disks in the broken device and put them in the other identical NAS. Would it then boot up and will I be abkle to access the data?

Any help would be appreciated.
Whenever I attempt to connect to the MD3200 Direct Attach Storage device using the PowerVault Modular Disk Storage Manager, I get the following on both nodes that can connect to it:

This storage array contains a RAID controller module you have not added.  You can launche its Array Management Window but any operations that must access the unknown RAID controller module will fail.  Use the Partially Managed Storage Arrays option to display the unknown RAID Controller module and add its appropriate host name or IP address.

The MD3200 shows as OPTIMAL and shows no alarms at all.  It has one disk pool that I can change the preferred path on at will with no problems.  

The Partially Managed Storage Arrays shows the following:

HostName/IPAddress                   StorageArray                  RAID Controller Module
0:0:0:0:0:0:1                                HARLEYDAVIDSON             RAID Controller Module in Slot B
HOST1                                         HARLEYDAVIDSON              RAID Controller Module in Slot B                                     HARLEYDAVIDSON              RAID Controller Module in Slot B
<UNKNOWN>                            HARLEYDAVIDSON              <UNKNOWN>

From the other node it shows the following:
HostName/IPAddress                   StorageArray                  RAID Controller Module
0:0:0:0:0:0:1                                HARLEYDAVIDSON             RAID Controller Module in Slot A
HOST2             …
Just specing out a server, single host to run 4 VMs, Going with a Dell Poweredge Perc h 730p.   with 2 GB of RAM on the controller.  How much does the RAM on the controller really impact performance?  Nothing is tremendously I/O intensive.  Would there be a substantial difference if I could update it to 4GB?

need to take 2 single drive  and create a raid5. One  drive is c (bay1) the other is d drive (bay 2)need to put both drives on  a single volume HP ML 350 with e200 raid controller. bay1 is c drive bay 2 is drive need to create 1 volume raid 5 Thanks
We are redesigning out current ZFS file server. It currently only has one pool of over 70TB.

I see this is a problem since, if there are enough disk failures within the pool to make it non-functional, we have to restore all 60TB of currently existing data.

A debate has risen as to how to divide up the storage into smaller pools, and how big/small each of those pools should be.

As I see it, the only drawback of using pools that are "too small" is a lot of wasted disk space. We are using `4TB 7500 spinning disks` with `4TB SSD cache disks`. So, I'm leaning towards 20TB raidz vdisks.  That means we get about 77% of the disk space usable.

Q: Are there any other advantages/disadvantages to making the pool sizes too large/too small?
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776 (Ready for Recovery) Logical Drive 1 (1.4 TB, RAID 5) is queued for rebuilding. hp server g5 ml350 server has been in this state for 2 weeks server has been restarted still says ready to rebuild not sure where to look next thanks
I have a PERC H330 card and would like to build an 18TB raid 5 array out of four HGST 6TB SAS disks. Two disks are 512b, 6Gb/s and the other two 4KB, 12Gb/s.

For some reason though I cannot add them into the same array. They work in separate raid 1 arrays but that isn't what I want.

Is it perhaps the case of an old firmware version on the PERC card (4.290.01-8335) or I simply cannot combine the two types of disks together?
Hello all,
I'm configuring an HP Z420 workstation with a 1TB SSD system drive (Boot /OS Drive) and two Enterprise 4TB SATA HDD for storing all my data in RAID1 . I wanted to know what the best RAID1 configuration would have the best performance for how I will be using it.

I mostly will use the workstation for document editing (word, excel, PDF, PowerPoint, Visio, etc.), internet , watching videos.

I plan to store A LOT of personal photos (thousands) in RAW format (each can be 15MB to 40MB) on the 4 TB RAID1.  I do some minor photo editing on photos using Google photos and I also store personal video files as well. I rarely edit videos and they are usually no more than 15min long but I do have a few longer than 1hr.

The workstation has the following RAID CARD:
LSI Logic SAS9260-8I SGL -8PORT, Int 6GB SAS/sata,  Pcie 2.0, 512MB RAID Card WITH a battery backup on the card itself. I also have a UPS for the computer as well.

The RAID configuration page has the following options (Image attached):
- Raid Level (I chose RAID 1)
-Stripe Size ( the options here are- 8kb, 16kb, 32kb, 64kb, 128kb, 256kb, 512kb, 1MB)
-Access Policy (RW is the default)
-Read Policy (options here are- Normal or Ahead)
-Write Policy (I chose Write Back with BBU since I have the Battery backup unit but other options are Write through, Always write back, write back w/ BBU)
-IO Policy (Options here are- Direct or Cached)
-Drive Cache (Options here are- NoChange, Enable or Disable)
We have Dell r730 running Solaris 11 and MD1420 storage array connected through perc h830 raid controller. MegaCli is unable to collect disk information.

The command is /MegaCli -PdList -a0

and the error we get is:
ERROR:Could not detect controller.
Failed to get ControllerId List.
Failed to get CpController object.

Any suggestions? Is there a different software that can be used under Solaris 11. Mainly we are trying to check disk status every few hours through cron job, so that any disk failure can be notified through email in a timely manner.

Similar hardware running Solaris 10 x86 works fine.

/MegaCli -PdList -a0 | grep -i "Firmware state"
Firmware state: Online, Spun Up
Firmware state: Online, Spun Up
I have a desktop computer (Alienware) with four internal hard disks, with a RAID motherboard.  Two of the disks are striped (the c:\ drive) and the other two disks are mirrored (the d:\ drive) and contain all my data.  The c:\ drive contains my operating system (Windows 7) and all my programs.  I want to replace the c:\ drive disks with 2 SSDs.  I want to clone the c:\ drive and then transfer this clone to the 2 SSDs, which will constitute the new striped c:\ drive.  I have cloned and transferred an old hdd's content to a new SSD, but without RAID.  It was easy.  But how do I do the same with a RAID system?  I'm at a loss as to how to proceed.  

Thanks, WmABradnan
I am looking to build a cheap storage device using a DELL perc H330 PCIE RAID adapter and a few HGST 6TB SAS disks.

I tried using a couple of older (6+ years) desktop motherboards but neither of them would allow the RAID controller as a boot device.

Can you please recommend something relatively cheap that's proven to work in this scenario? UK market preferrably, can be second hand.
Hello everyone.

For starters, I do not make a lot of money in my self-business.
So, I have to get what I can get, in order to grow.
With that said.

I have just purchased an Intel SR2500ALBRP
The motherboard: S5000PAL

In the following image, you will see a BLUE set of SATA cables with a single PLUG at the end.
Intel SR2500ALBRP RAID SATA Connector
Now, The PCI riser assembly has only a NIC Card on it with DUAL 1G nics.
My question is simple.
WHAT RAID Card do I need to get, to connect this with?

We have an MD3200 for storage in our HYPERV cluster.  We used the wizard to create a pool on the MD3200 which seems to have set aside 2 disks for redundancy (basically, a RAID 6, I believe).

I create a virtual disk in the pool, I wanted to use up all the available space.  However, the MD3200 starts complaining about > 80% (I believe the default) of the pool being used up.  Can I just turn that off or do I truly need to ensure the virtual disk takes up less than 80% of the space of the pool?

Hi, I have an odd question that would like to know what others are doing these days.  I know keep doing the same thing because that is they way it has always been done, isn't the best choice.

I am setting up a RAID 1 array on a HPE ProLiant DL360 Gen10 server with Smart Array P408i-a.  In addition, I have 3 HPE 300GB SAS / 12Gb/s HDD's.

So, my intent is to setup a RAID 1 array with a hot spare.

This will be supporting a Windows Server 2016 - Standard domain controller.

With all that being said, what strip size would you use in this scenario?  64KiB?  128KiB?  256KiB?

Currently, the default is 256KiB.

Just curious.

Thanks in advance.
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I can't get one of my servers to power up. I don't believe it's a hard drive issue, more importantly for the sake of this question, I don't believe it's a hard drive issue. How do I recover data from the RAID?
RAID levels 0 and 1 can be combined to make a stripe of mirrors (RAID 10) or a mirror of stripes (RAID 01) configuration.  Which implementation would you prefer to use and why?
Dear Experts

I have a question related to controller M1015. I want to use it in IT mode for Unraid server.

In specification I can read this:
The ServeRAID M1015 SAS/SATA Controller has the following specifications:

Eight internal 6 Gbps SAS/SATA ports
Supports SAS and SATA drives (but not in the same RAID volume)
Two Mini-SAS internal connectors (SFF-8087)
6 Gbps throughput per port
LSI SAS2008 6 Gbps RAID on Chip (ROC) controller
x8 PCI Express 2.0 host interface
Supports RAID levels 0, 1, 10 (RAID levels 5 and 50 with optional ServeRAID M1000 Series Advanced Feature Key)
Connects to up to 16 SAS or SATA drives
Supports up to 16 logical volumes
Supports LUN sizes up to 64 TB
Configurable stripe size up to 64 KB
Compliant with Disk Data Format (DDF) configuration on disk (COD)
S.M.A.R.T. support

What I do not understand is - does this controller allows to connect 16 physical SATA drives? If yes why it reports only 8 internal ports?

many thanks for your advice

Good day,
We have a VM host that runs two server machines.  The first is the DC/FS and it works great.  The second machine is a terminal server.  It constantly is freezing on the users and it is getting frustrating.  Here is some info:

Host machine is running Server 2016 Standard.  Its specs are:

HPE Proliant DL380 G9
Xeon E5-2620 v3
RAID 10 for the virtual disks

Server is stable, no issues.

The host machine allocates a large portion of RAM to the DC and the TS.  The DC currently has 8GB and 8 virtual processors.  The TS has 10GB RAM, and also 8 virtual processors.  Originally I had the TS with less RAM and processors, but in trying to fix the freezing issue, I increased the resources.  I plan on bringing them back down.

The TS has only 3 users signing in.  They use the same domain account to log in to the server.  The TS is configured to allow the same user to log in multiple times.  It is light usage.  The TS exists to run only one program.  While using that program, the users may open Word or Adobe, but not much of anything else.  About 4 or 5 times a day, the server just stops responding to that user.  The other users logged in do not experience the same.  It will just spin and spin.  The remote connection never breaks.  Frustrated, they just click the x on the top blue ribbon, and re-log back in.  Then its totally normal until it freezes again.  

During the freeze, the internet is working normally, the others users aren't affected.  A VPN …
Probably a fairly "classic" issue but I have surprisingly not found definitive info about it online.

What is the best practice managing hardware RAID controllers on ESX Hosts ? Ideally, we would like to be able to "reach out" to the controller from a Windows guest VM but if not possible at the very least have some management capability (expand RAID, check array consistency) from ESXCLI.

How should we go about it ? In our specific and immediate case ESX6.5 with Intel RMS25CB080 controller.
Can i convert a mdadm from raid 6 to raid 0

I have a machine with 10&10TB of data in raid 6.

I'm looking to convert to Raid 0

I dont really care if I lose the data (I have several copies) I just would prefer daving the time off wiping machine - raid 0 - then transferring it all back again.

Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdc1[2] sdi1[8] sdf1[5] sdj1[9] sdh1[7] sde1[4] sdg1[6] sdd1[3] sdb1[1] sda1[0]
      4190208 blocks super 1.2 [10/10] [UUUUUUUUUU]

md1 : active raid1 sdc2[2] sdi2[8] sde2[4] sdj2[9] sdg2[6] sdf2[5] sdh2[7] sdd2[3] sdb2[1] sda2[0]
      523712 blocks super 1.2 [10/10] [UUUUUUUUUU]

md3 : active raid6 sdc4[2] sdj4[9] sdi4[8] sde4[4] sdf4[5] sdg4[6] sdh4[7] sdd4[3] sdb4[1] sda4[0]
      75980845056 blocks super 1.2 level 6, 512k chunk, algorithm 2 [10/10] [UUUUUUUUUU]
      bitmap: 2/71 pages [8KB], 65536KB chunk

md2 : active raid6 sdc3[2] sdg3[6] sde3[4] sdi3[8] sdf3[5] sdj3[9] sdh3[7] sdd3[3] sdb3[1] sda3[0]
      2110783488 blocks super 1.2 level 6, 512k chunk, algorithm 2 [10/10] [UUUUUUUUUU]
      bitmap: 2/2 pages [8KB], 65536KB chunk


RAID stands for Redundant Array of Independent Disks.

RAID is data storage technology that allows multiple drives to be used together as a single virtual drive for reasons such as fault tolerance, reliability and performance.

There are several different levels of RAID that determine how the data is stored and the level of redundancy achieved across the drives.

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