[PVE-User] openiscsi with Proxmox

[Pongrácz István]

 Hi,

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>SLOG - dedicated device (partition) to hold ZIL on it instead of the pool (much quicker 
>than pool -> high iops for sync writes)
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>first of thanks for writing an informative input. 
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>as it seems, a person must need 1 SSD for L2ARC and 2xmirrored SSDs for ZIL, now the 
>question is do we also need a SSD for SLOG
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>ZIL is the write cache in memory. SLOG is like a raid1 mirror to ZIL located on storage. 
>This could be on dedicated SSD or in a partition on an SSD. In your case it could be enough to 
>make some partitions on a reliable SSD and use it for system (ext3/4), L2ARC (10-100GB?), 
>SLOG (1-2GB). Please remember, only sync writes goes to ZIL, in the worst case you lost 5 
>seconds of data if the SLOG device dies too. (no rule of thumb, you need to check your 
>implementation details)
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>Thanks Fabio, i have a dell workstation 490 and it only support SATAv2 or 3gb speed.
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>do you guys think by tweaking ZFS a bit and using multiple SSDs for ZIL, L2ARC and may be 
>SLOG can give me 4x1GB from each interface. as i mentioned i have 12GB RAM.
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>No idea. You should play with the tunings (compression, raidz2/3). Too much variables 
>(cpu throughput, your pool config, fragmentation of course - COW, IO direction). I have a 
>AMD T56N system with 2 x sata port multiplicators with 6x 2.5" hitachi disks, I can achieve 
>50MB/sec write to them with no compression - video, but sometimes it droppes to 10-20MB/sec.
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>So, you should test your system and monitor it.
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>we are a small company, not too much reads and writes, we mostly checkin checkout our 
>software codes to the VM repositories.
>so i think generally we have less IOPS but yes we have huge files in form of VMs and they 
>should be backed up every week and snapshot ZFS on daily basis
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>Raidz2/3 could be ok, depends on numbers of your disks.
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>so with this load what you guys think, can i achieve 4x1gb Ethernet output?
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