11

Windows Parity Spaces are dog slow and (according to Microsoft) aren’t designed for anything except archive workloads. Microsoft keeps trying to improve write performance say implemented log missing from the hardware RAIDs, but lack of the battery-powered write back cache takes away all the fun. You can however try to improve writes by telling Spaces you ...


8

Slabs which are file system cluster equivalents are quite big. So yes, you’ll get fragmentation but no, you won’t notice any performance impact. Really.


8

This postponed write happens because of a a) file system level write-back RAM cache, and b) parity Spaces design, which absorbs all the writes to the internal log initially to avoid “read-modify-write” on the “critical path” dramatic slowdown. When your write is complete file system keeps flushing data in the “lazy writer” worker thread and Spaces keep ...


7

ReFS by itself cannot repair corruptions, it is a feature of Storage Spaces. But ReFS will detect them when on files with data integrity stream enabled when reading the corrupted block, or when ReFS data scrubber encounters the corrupted block during its patrol reads. ReFS is a "new" file system and its stability of ReFS for long-term backup repository is ...


6

"Windows Storage Spaces - a useful replacement for RAID6?" If by "RAID6" you mean "I hate my data and want to get to it in as slow a way as possible" then yeah, sure - we lost 62TB of data to it at one point, luckly had a backup of it all but never again. EDIT: Don’t trust to Windows software RAID, don’t trust to double parity ...


6

RAID5 (just like any parity RAID, f.e. RAID6 or RAID4) has to read the data before applying writes regardless of cache or no-cache on controller. See: Read-Modify-Write Vs. Read-Construct-Write Windows Storage Spaces are infinitely slow (esp. dual parity which is diagonal parity actually taken nearly AS IS from Azure, see Erasure Coding in Azure) so if you ...


4

Be aware of the fact tiering with ReFS + Windows Server 2019 works in a totally different way compared to NTFS + Windows Server 2016. 2016: All writes go to the flash tier with the data being offloaded to spinning disk when flash is getting full / close to being full (~80% usable capacity occupied AFAIR). 2019: All writes go immediately to the spinning ...


4

You can check it in the Performance Monitor. Add Physical disks Read and Write counters for your SSDs and HDDs. In this case, you will be able to see which Tier is being utilized by seeing which drives are doing IO. In addition, configure ReFS counter of fast and slow tiers utilization percentage. This information will give you data distribution between ...


4

As long as you use Enterprise grade SSDs, ones coming with either battery or capacitor power loss protection you’ll be fine. Physical form factor and attachment type are irrelevant. https://techcommunity.microsoft.com/t5/storage-at-microsoft/don-t-do-it-consumer-grade-solid-state-drives-ssd-in-storage/ba-p/425914


3

Generally speaking Storage Spaces aren’t supported for anything except raw disks AND virtual disk instances in Azure only, so you’re dealing with an unsupported configuration straight away... You can snapshot individual drives but there’s no guarantee you’ll get some consistent state, there’s no VSS-like concept for Storage Spaces SLABs. Snapshots aren’t ...


3

Consider Hardware RAID over Software RAID as it has no OS dependencies. Make OS RAID 1 as you plan to do it for the storage. What is the guest OS? Consider RAID 5 with HDDs for the case it is more a "read-intensive" lab. Otherwise RAID 5 will bring you the capacity of two disks and write the performance of a single one.


3

Generally speaking you will want to keep hardware- and software based storage solutions separate: Both want direct access to the disks to do their job properly, and there's a high chance they'll trip each other up if combined. The general recommendation is to use an HBA rather than a RAID controller for software driven storage. A - or rather the - benefit ...


3

I assume you are using Storage Spaces Direct. In this case you would need to add NVMe drives to be able to use SSDs for capacity Tier. More information: https://docs.microsoft.com/en-us/windows-server/storage/storage-spaces/understand-the-cache. You will need to add more HDDs to your server to be able to extend you CSVs.


2

If you have a look at the docs for expanding disks in storage spaces it has this warning: Not supported: resizing the underlying storage used by Storage Spaces Direct. If you are running Storage Spaces Direct in a virtualized storage environment, including in Azure, resizing or changing the characteristics of the storage devices used by the virtual ...


2

You can do S2D bare metal only. Storage Spaces (Direct) are unsupported inside the VMs (except Azure, but that’s another story to tell).


1

Open-iSCSI, the Linux iSCSI initiator, doesn't appear to have any built in limits and should support LUNs up to the maximum size of a block device on that particular Linux kernel, which as best I can tell is currently 16 EB (subscription required). Your storage server is unlikely to be able to provide LUNs this large. For instance NetApp does not support ...


1

Please verfiy that after the update if any other changes made on the paths to the storage Switches. Also verify that OS level changes you made are still compatible with code level on the XIV. https://www-03.ibm.com/systems/support/storage/ssic/interoperability.wss Also update to the lastest XIV HAK https://www.ibm.com/support/knowledgecenter/...


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