Search results for query: raidz1 padding

You won't only loose the redundancy, you will also loose features like your bit rot protection that can't work without a form of parity. With a stripe your ZFS still can detect data corruptions and tell you "your data got corrupted" but it can't repair it anymore because there is no parity. With...

If you use a volblocksize of 8K with raidz1 you will loose 25% of your raw capacit to parity and 25% of your raw capacity to padding overhead (in other words for every 2 blocks of data you get 1 block of padding so eveything is 50% bigger). If you want to minimize padding overhead you need to...

Thank you very much for the input. I'm a bit lost as to why this is even an option? What are the benefits of block sizing at 8k vs 16k?

All the images are bigger because of padding overhead. If your pool was created using ashift=12 with 3 disk raidz1 you would need atleast a volblocksize of 16K. If you created all your virtual disks with the default volblocksize of 8K you will loose 33% of your raw capacity to parity + 17% of...

You don't use ZFS because you want raid. ZFS should be used if you want raid and you want to be sure that the data won't corrupt. And because you want CoW, a self-healing filesystem, compression on block level, deduplication, replication, snapshots and so on. All stuff that a HW raid controller...

If you use 6x 1TB as raidz1 and dont increase the volblocksize you only get 3TB of total storage because you are loosing 1TB to parity and 2TB to padding. So you cant create a 4TB zvol because you only got usable 2,4TB (10-20% always should be kept unused) of storage. That padding overhead is...

I got the same mainboard and ECC RAM (and yes, its RGB ECC XD) for my Gaming PC. Keep in mind that only one of the M.2 slots is connected to the CPU. The other one is connected to the mainboards chipset and will share the same bandwidth (4 PCIe 4.0 lanes) with all the other stuff on the...

Ok thanks for your help. This will also adjust if I just migrate the machine too? rather than backup/restore.

For striped pools you want blocksize of your pool (so 4K if ashift of 12 is used) multiplied by the number of data bearing disks. So if you got two mirrors of each 2 SSDs striped together using ashift of 12 that is 2 * 4K = 8K. For raidz it is more complex. Here is a table that show...

Look at this spreadsheet. With a raidz1 of 8 disks and ashift of 12 you would loose: volblocksize 4K/8K = 50% raw capacity lost volblocksize 16K = 33% raw capacity lost volblocksize 32K/64K = 20% raw capacity lost volblocksize 128K = 16% raw capacity lost volblocksize 256/512K = 14% raw capacity...

What is your ashift? If you sync write 512B blocks to a pool that is setup with a ashift of 12 (4K block size) you get massive write amplification. Never write blocks that are smaller then your smallest block size. Also your consumer SSDs got no powerloss protection so they can't cache sync...

Thats why I see atleast one person every week starting a new thread like "my storage is too small" and they don't get that just creating VMs without optimizing the volblocksize first is most of the time wasting TB or dozens of TBs of storage space. Especially if some kind of raidz is used where...

That the padding overhead. When using raidz1 with 4 drives, ashift=12 and a volblocksize of 8K you will loose 25% of the raw capacity to parity and another 25% of raw capacity to padding. So ZFS will tell you you got 1.5TB of usable capacity but everything is 150% in size again, so after using...

Actually, no luck, because setting the block size to 40k then recreating the hard disks in the VM results in the error: zfs error: cannot create 'bpool/vm-100-disk-0': 'volblocksize' must be power of 2 from 512B to 1M

Like I already said, increase the volblocksize to something like 40K and recreate the zvols (or create a backup and restore it) and you should only loose 17% of the raw capacity to parity instead of 67% (17% parity+50%padding) of the raw capacity. And this has nothing to do with 512B in Win or...

No, you read the table wrong. Rows are volblocksize in sectors. If you got a disk with 512B LBA and have chosen ashift=9 for the pool the 8K volblocksize is the row with "16" (8K volblocksize / 512B sectorsize = 16 sectors). But your pool was probably created with a ashift=12 so your sectors are...

several things here. #1 raidz-1 isnt optimal at all. its like a raid5 and with such big disks not that fault tollerant as you might think. theres a chance loosing a junk. also 4disks are suboptimal for either. problem is not total capacity but high capacity over 1.5tb a drive. in any case you...

You can look at this table. With 8K (= 2 sectors at ashift 12) volblocksize you will loose 50% of your total raw capacity due to parity and padding. With 12K, 24K, 36K, 48K ( = 3, 6, 9, 12 sectors) and so on you would only loose 25% of your total raw capacity. So I would test it with 12K...

No result : # zpool list NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT data 7.27T 114G 7.15T - - 0% 1% 1.00x ONLINE - rpool 149G 16.5G 133G - - 0% 11% 1.00x ONLINE - # zfs list NAME...

Let me guess...you are using a raidz1/2/3 pool and didn't increased the volblocksize from 8K to something higher? In that case you are wasting space because of bad padding. Solution would be to increase the "Block size" for that pool (look at these 6 spreadsheets to get an idea of what...