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Dual parity drives setup, to possibility double the write speeds in unraid...

Featured Replies

FYI, just a note as to why I bother setting up the ARECA in the SAFE33 environment.

 

My parity drive is always spinning during the day. I access the data drives constantly over the internet from work.

One of my data drives which handles torrents is spinning all the time too.

 

Since I have two drives spinning all the time, It makes sense for me to set up a carved up SAFE environment.

RAID0/RAID1 and let the two drives spin, but also do double duty.

 

So I get faster parity writes, and a fast protected area for my torrents or other application servers. (mysql, cache drive, consolidated syslog host, etc, etc).

WeeboTech, great work as always. A couple more questions, mostly exploring what options are available in the Safe33 setup.

 

On the Raid-1 portion, can it be partitioned to support cache disk and linux swap? Can it be further partitioned for a full Slackware install? If so, can one boot from there? Or does it need the hardware drivers loaded before it's able to read from there?

WeeboTech, great work as always. A couple more questions, mostly exploring what options are available in the Safe33 setup.

 

On the Raid-1 portion, can it be partitioned to support cache disk and linux swap? Can it be further partitioned for a full Slackware install? If so, can one boot from there? Or does it need the hardware drivers loaded before it's able to read from there?

 

To the OS. each of the Raid Volumes looks like a regular drive.

So it can be partitioned as you mention.

 

Tom gave us instructions a while back on the board.

 

The First Partition (#1) must be the cache drive and needs to be #1.

Any other partitions are not used.

 

So if you set up 4 partitions as

1. cache

2. swap

3. slackware

 

The raid1 drive can be used and booted. I have not tried it yet, but plan to.

Although I will be setting up partition #4 as fat32 and putting the syslinux unraid Distro there.

Then in the slackware dev system, I'll mount it on /unraid/boot so I can update it from slackware.

 

 

Just so it is clear, The SAFE50/SAFE33 is a Silcon Image Chipset notation for dividing up two drives.

I called it that because I have it the same way.

 

On the ARECA bios it is called a RAIDSET (# of drives which are linked together).

Then a VOLUME SET (These are the RAIDSET drives which are carved up, 1 volume RAID0, 1 Volume RAID1).

I suppose if you had a 3rd drive, it could be part of the RAID Set and a hot spare for the RAID1 volume.

 

In any case, these can be carved up in any respective sizes.

I used two 1.5tb drives and had a full 2TB volume (Which was actually larger then a 2TB drive by a small margin).

Then used the rest for the RAID1 volume. This came out to about 400GB.

Weebotech, it's good to know that's a possibility. I currently have my system setup similarly on a single drive (cache / swap / win os / slackware).

 

What I am curious about is how does a raid-0 set of 5400/Green drives perform with a 7200 rpm (or even SSD) data drive. Is the raid0 between two slower drives enough to counteract their higher latency?

 

At first when you mentioned you found a way to speed up parity, I thought maybe you worked something out with tweaking of filesystem/device buffers or even using multithreading for a) reading into a buffer b) calculating parity from the buffer.

What I am curious about is how does a raid-0 set of 5400/Green drives perform with a 7200 rpm (or even SSD) data drive. Is the raid0 between two slower drives enough to counteract their higher latency?

 

I'll have to test it out, although I'm not sure it is the best way to go. I'm sure the caching controller helps in this situation.

 

At first when you mentioned you found a way to speed up parity, I thought maybe you worked something out with tweaking of filesystem/device buffers or even using multithreading for a) reading into a buffer b) calculating parity from the buffer.

 

I have not gone that route, still. Adjusting the scheduler or md stripe parameters could have an effect if we can write to the parity drive faster.

 

although, I think where the RAID0 helps is in the reads.  The samsung Spinpoint F3 1TB's benchmark at up to 149MB/s reads.  really stellar numbers if you ask me.

 

I would be curious to see how two Hitachi 7K 2TB drives perform. I would have purchased them only I read they run pretty hot.

FWIW, some benchmarks.

 

 

This is raw write/read speed.

2 samsung spinpoint F3 1tb 7200rpm 32MB cache.

 

This is more like a SAFE10

 

root@unraid ~ #df -vH

Filesystem            Size  Used  Avail Use% Mounted on

/dev/sdh1              518M  491M    28M  95% /boot

/dev/sdb1              150G    34M  150G  1% /mnt/sdb1 RAID1

/dev/sda1              1.7T    34M  1.7T  1% /mnt/sda1  RAID0

 

 

Areca RAID0

root@unraid ~ #writeread10gb /mnt/sda1/test.dd

writing 4096000000 bytes to: /mnt/sda1/test.dd

726015+0 records in

726015+0 records out

743439360 bytes (743 MB) copied, 5.0064 s, 148 MB/s

1383311+0 records in

1383311+0 records out

1416510464 bytes (1.4 GB) copied, 10.0211 s, 141 MB/s

2090981+0 records in

2090981+0 records out

2141164544 bytes (2.1 GB) copied, 15.0351 s, 142 MB/s

2861533+0 records in

2861533+0 records out

2930209792 bytes (2.9 GB) copied, 20.125 s, 146 MB/s

3518678+0 records in

3518678+0 records out

3603126272 bytes (3.6 GB) copied, 25.0605 s, 144 MB/s

4000000+0 records in

4000000+0 records out

4096000000 bytes (4.1 GB) copied, 28.0151 s, 146 MB/s

write complete, syncing

reading from: /mnt/sda1/test.dd

4000000+0 records in

4000000+0 records out

4096000000 bytes (4.1 GB) copied, 9.29826 s, 441 MB/s

removing: /mnt/sda1/test.dd

removed `/mnt/sda1/test.dd'

root@unraid ~ #

 

 

Areca RAID1 volume set (inside tracks)

root@unraid ~ #writeread10gb /mnt/sdb1/test.dd

writing 4096000000 bytes to: /mnt/sdb1/test.dd

505597+0 records in

505597+0 records out

517731328 bytes (518 MB) copied, 6.03984 s, 85.7 MB/s

898253+0 records in

898253+0 records out

919811072 bytes (920 MB) copied, 10.3446 s, 88.9 MB/s

1354112+0 records in

1354112+0 records out

1386610688 bytes (1.4 GB) copied, 15.0395 s, 92.2 MB/s

1813101+0 records in

1813101+0 records out

1856615424 bytes (1.9 GB) copied, 20.3317 s, 91.3 MB/s

2215710+0 records in

2215710+0 records out

2268887040 bytes (2.3 GB) copied, 25.0659 s, 90.5 MB/s

2598413+0 records in

2598413+0 records out

2660774912 bytes (2.7 GB) copied, 30.3255 s, 87.7 MB/s

2992421+0 records in

2992421+0 records out

3064239104 bytes (3.1 GB) copied, 35.0916 s, 87.3 MB/s

3383725+0 records in

3383725+0 records out

3464934400 bytes (3.5 GB) copied, 40.2116 s, 86.2 MB/s

3855033+0 records in

3855033+0 records out

3947553792 bytes (3.9 GB) copied, 45.1206 s, 87.5 MB/s

4000000+0 records in

4000000+0 records out

4096000000 bytes (4.1 GB) copied, 46.8394 s, 87.4 MB/s

write complete, syncing

reading from: /mnt/sdb1/test.dd

4000000+0 records in

4000000+0 records out

4096000000 bytes (4.1 GB) copied, 21.1475 s, 194 MB/s

removing: /mnt/sdb1/test.dd

removed `/mnt/sdb1/test.dd'

 

 

 

and s'more numbers in this configuration.

 

 

 

2 Seagate 1.5tb RAID0 outer tracks parity

2 Seagate 1.5tb RAID1 inner tracks /mnt/cache

 

1 ata-SAMSUNG_HD103SJ /mnt/disk1

1 ata-WDC_WD20EADS    /mnt/disk2

 

 

root@unraid ~ #df -vH

Filesystem            Size  Used  Avail Use% Mounted on

/dev/sdh1              518M  491M    28M  95% /boot

/dev/sdb1              401G    34M  401G  1% /mnt/cache

/dev/md1              1.1T    34M  1.1T  1% /mnt/disk1

/dev/md2              2.1T    34M  2.1T  1% /mnt/disk2

 

 

writing 4096000000 bytes to: /mnt/cache/test.dd

448525+0 records in

448525+0 records out

459289600 bytes (459 MB) copied, 5.01436 s, 91.6 MB/s

764669+0 records in

764669+0 records out

783021056 bytes (783 MB) copied, 10.811 s, 72.4 MB/s

1027789+0 records in

1027789+0 records out

1052455936 bytes (1.1 GB) copied, 15.2366 s, 69.1 MB/s

1420445+0 records in

1420445+0 records out

1454535680 bytes (1.5 GB) copied, 20.3366 s, 71.5 MB/s

1813101+0 records in

1813101+0 records out

1856615424 bytes (1.9 GB) copied, 25.5465 s, 72.7 MB/s

2145394+0 records in

2145394+0 records out

2196883456 bytes (2.2 GB) copied, 30.083 s, 73.0 MB/s

2468877+0 records in

2468877+0 records out

2528130048 bytes (2.5 GB) copied, 37.9191 s, 66.7 MB/s

2667229+0 records in

2667229+0 records out

2731242496 bytes (2.7 GB) copied, 40.1651 s, 68.0 MB/s

2991069+0 records in

2991069+0 records out

3062854656 bytes (3.1 GB) copied, 45.5686 s, 67.2 MB/s

3254189+0 records in

3254189+0 records out

3332289536 bytes (3.3 GB) copied, 50.2236 s, 66.3 MB/s

3646845+0 records in

3646845+0 records out

3734369280 bytes (3.7 GB) copied, 55.3009 s, 67.5 MB/s

4000000+0 records in

4000000+0 records out

4096000000 bytes (4.1 GB) copied, 59.481 s, 68.9 MB/s

write complete, syncing

reading from: /mnt/cache/test.dd

000000+0 records in

4000000+0 records out

4096000000 bytes (4.1 GB) copied, 33.197 s, 123 MB/s

removing: /mnt/cache/test.dd

removed `/mnt/cache/test.dd'

 

write to parity protrected samsung 1tb drive.

 

root@unraid ~ #writeread10gb /mnt/disk1/test.dd

writing 4096000000 bytes to: /mnt/disk1/test.dd

279896+0 records in

279896+0 records out

286613504 bytes (287 MB) copied, 5.0469 s, 56.8 MB/s

497737+0 records in

497737+0 records out

509682688 bytes (510 MB) copied, 10.0713 s, 50.6 MB/s

709625+0 records in

709625+0 records out

726656000 bytes (727 MB) copied, 15.0388 s, 48.3 MB/s

931833+0 records in

931833+0 records out

954196992 bytes (954 MB) copied, 20.0544 s, 47.6 MB/s

1110009+0 records in

1110009+0 records out

1136649216 bytes (1.1 GB) copied, 25.0654 s, 45.3 MB/s

1314809+0 records in

1314809+0 records out

1346364416 bytes (1.3 GB) copied, 30.0813 s, 44.8 MB/s

1547265+0 records in

1547265+0 records out

1584399360 bytes (1.6 GB) copied, 35.2883 s, 44.9 MB/s

1754113+0 records in

1754113+0 records out

1796211712 bytes (1.8 GB) copied, 41.0101 s, 43.8 MB/s

1926145+0 records in

1926145+0 records out

1972372480 bytes (2.0 GB) copied, 45.1903 s, 43.6 MB/s

2147329+0 records in

2147329+0 records out

2198864896 bytes (2.2 GB) copied, 50.1333 s, 43.9 MB/s

2367533+0 records in

2367532+0 records out

2424352768 bytes (2.4 GB) copied, 55.1457 s, 44.0 MB/s

2595841+0 records in

2595841+0 records out

2658141184 bytes (2.7 GB) copied, 61.0117 s, 43.6 MB/s

2768830+0 records in

2768830+0 records out

2835281920 bytes (2.8 GB) copied, 65.1832 s, 43.5 MB/s

2984325+0 records in

2984324+0 records out

3055947776 bytes (3.1 GB) copied, 70.1872 s, 43.5 MB/s

3200014+0 records in

3200014+0 records out

3276814336 bytes (3.3 GB) copied, 75.1947 s, 43.6 MB/s

3425281+0 records in

3425281+0 records out

3507487744 bytes (3.5 GB) copied, 80.2551 s, 43.7 MB/s

3606537+0 records in

3606537+0 records out

3693093888 bytes (3.7 GB) copied, 85.7637 s, 43.1 MB/s

3786769+0 records in

3786769+0 records out

3877651456 bytes (3.9 GB) copied, 90.2319 s, 43.0 MB/s

3999761+0 records in

3999761+0 records out

4095755264 bytes (4.1 GB) copied, 95.3352 s, 43.0 MB/s

4000000+0 records in

4000000+0 records out

4096000000 bytes (4.1 GB) copied, 95.3366 s, 43.0 MB/s

write complete, syncing

reading from: /mnt/disk1/test.dd

4000000+0 records in

4000000+0 records out

4096000000 bytes (4.1 GB) copied, 22.956 s, 178 MB/s

removing: /mnt/disk1/test.dd

removed `/mnt/disk1/test.dd'

 

write to parity protected eads2tb

root@unraid ~ #writeread10gb /mnt/disk2/test.dd

writing 4096000000 bytes to: /mnt/disk2/test.dd

236065+0 records in

236065+0 records out

241730560 bytes (242 MB) copied, 5.33615 s, 45.3 MB/s

408561+0 records in

408561+0 records out

418366464 bytes (418 MB) copied, 10.6804 s, 39.2 MB/s

582641+0 records in

582641+0 records out

596624384 bytes (597 MB) copied, 15.0393 s, 39.7 MB/s

740337+0 records in

740337+0 records out

758105088 bytes (758 MB) copied, 20.1382 s, 37.6 MB/s

898253+0 records in

898253+0 records out

919811072 bytes (920 MB) copied, 25.0746 s, 36.7 MB/s

1068525+0 records in

1068525+0 records out

1094169600 bytes (1.1 GB) copied, 30.0627 s, 36.4 MB/s

1213425+0 records in

1213425+0 records out

1242547200 bytes (1.2 GB) copied, 35.0884 s, 35.4 MB/s

1392625+0 records in

1392625+0 records out

1426048000 bytes (1.4 GB) copied, 40.095 s, 35.6 MB/s

1552369+0 records in

1552369+0 records out

1589625856 bytes (1.6 GB) copied, 45.0936 s, 35.3 MB/s

1719281+0 records in

1719281+0 records out

1760543744 bytes (1.8 GB) copied, 50.2372 s, 35.0 MB/s

1876977+0 records in

1876977+0 records out

1922024448 bytes (1.9 GB) copied, 55.1139 s, 34.9 MB/s

2045697+0 records in

2045697+0 records out

2094793728 bytes (2.1 GB) copied, 60.124 s, 34.8 MB/s

2204657+0 records in

2204657+0 records out

2257568768 bytes (2.3 GB) copied, 65.1355 s, 34.7 MB/s

2371569+0 records in

2371569+0 records out

2428486656 bytes (2.4 GB) copied, 70.1927 s, 34.6 MB/s

2534385+0 records in

2534385+0 records out

2595210240 bytes (2.6 GB) copied, 75.1587 s, 34.5 MB/s

2710513+0 records in

2710513+0 records out

2775565312 bytes (2.8 GB) copied, 80.1699 s, 34.6 MB/s

2883473+0 records in

2883473+0 records out

2952676352 bytes (3.0 GB) copied, 85.1825 s, 34.7 MB/s

3038193+0 records in

3038193+0 records out

3111109632 bytes (3.1 GB) copied, 90.1961 s, 34.5 MB/s

3203057+0 records in

3203057+0 records out

3279930368 bytes (3.3 GB) copied, 95.2295 s, 34.4 MB/s

3364849+0 records in

3364849+0 records out

3445605376 bytes (3.4 GB) copied, 100.261 s, 34.4 MB/s

3528689+0 records in

3528689+0 records out

3613377536 bytes (3.6 GB) copied, 105.337 s, 34.3 MB/s

3703793+0 records in

3703793+0 records out

3792684032 bytes (3.8 GB) copied, 110.236 s, 34.4 MB/s

3861489+0 records in

3861489+0 records out

3954164736 bytes (4.0 GB) copied, 115.245 s, 34.3 MB/s

4000000+0 records in

4000000+0 records out

4096000000 bytes (4.1 GB) copied, 119.234 s, 34.4 MB/s

write complete, syncing

reading from: /mnt/disk2/test.dd

4000000+0 records in

4000000+0 records out

4096000000 bytes (4.1 GB) copied, 29.4291 s, 139 MB/s

removing: /mnt/disk2/test.dd

removed `/mnt/disk2/test.dd'

 

 

 

Weebotech, it's good to know that's a possibility. I currently have my system setup similarly on a single drive (cache / swap / win os / slackware).

 

BRiT, could you please share how have you done the partitioning and activation of the drive. I plan something similar with cache/swap/TimeMachine partitions on the same drive (minus the OS'es however). Perhaps also holding the SlimCenter binaries but not sure on that. This drive I don't want to be protected at all but it should be checked and spun down if there is no activity on it (perhaps cron job each hour?). Thanks!

So many "hidden" resources :-) Thanks much!

  • 2 months later...

Why Not add a Second parity drive simply for redundancy / additional fail safe. It seems to me that the Achilles heel of the unraid system is the single parity drive. If several data drives fail you can always reconstruct the data from the parity. But if the parity & a data drive fail all data would be lost.

 

A dual parity setup would effectively be like a raid 6 and provide much much greater fault redundancy

 

Why not add the option for a second parity drive?

You don't understand how unRAID works to make that statement. It's not true in unRAID's case.

 

With unRAID, if you lose the parity drive and a data drive, you only lose the contents on that single data drive. All the other data drives are perfectly fine.

Archived

This topic is now archived and is closed to further replies.

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